ASUS GTX 770 DirectCU II OC Review

With the acclaimed DirectCU II cooler and a factory overclock, the ASUS GTX 770 DirectCU OC looks the business. We see if it has the power to match those looks…

Product on Review: GTX770-DC2OC-2GD5
Manufacturer and Sponsor: ASUS
Street Price: £339.95 (At time of review)

The NVIDIA GTX770 has had a luke warm reception by all accounts. Based on the older GTX680 rather than the ground breaking GTX TITAN/GTX 780, many look upon the GTX770 as a simple refresh. To be fair, that is not far from the truth but NVIDIA have not simply raised the clockspeeds and have done with it. Improved power delivery, memory overclocking and GPU Boost 2.0 make the GTX770 quite a formidable GPU. There are however few reference designs available with NVIDIA giving their board partners free reign to add their own modifications. Some chose simply to bolt on a custom cooling design to the reference PCB. Others added to the modifications by redesigned the PCB. The ASUS GTX 770 DirectCU II OC is one such example.

With temperature control being very important when overclocking via GPU BOOST 2.0, the ASUS card is duly equipped with with the latest incarnation of Direct CU cooling. For those not already aware the DirectCU II cooling design is held in very high regard by the media and enthusiasts alike thanks to both performance and acoustics. The card also comes pre-overclocked from the factory and should you wish to dabble yourself, this version of the GTX 770 has a 10 phase power design for stable power delivery complete with DIGI+ power regulation. For the serious overclockers, the card also has voltage read points and identified solder points for voltage hot wiring. So whichever your preference, the ASUS card appears to suit all tastes.

ASUS takes its name from Pegasus, the winged horse in Greek mythology that symbolises wisdom and knowledge. ASUS embodies the strength, purity, and adventurous spirit of this fantastic creature, and soars to new heights with each new product it creates.

This visionary approach is the reason ASUS is able to bring high-quality innovation and design to all, and the reason for its widespread acclaim. ASUS products won 4,168 international awards and accolades in 2012 – that’s over 11 a day, every day. ASUS has consistently achieved significant year-on-year growth in terms of consumer notebook units shipped too, and closed 2011 on a high with revenues hitting US$11.9 billion.

Specification

Graphics Engine: NVIDIA GeForce GTX 770
Bus Standard: PCI Express 3.0
Video Memory: GDDR5 2GB
Engine Clock:GPU Boost Clock – 1110 MHz, GPU Base Clock : 1058 MHz
CUDA Core: 1536
Memory Clock: 7010 MHz ( DDR2 )
Memory Interface: 256-bit
Interface: DVI Output : Yes x 1 (DVI-I), Yes x 1 (DVI-D), HDMI Output : Yes x 1, Display Port : Yes x 1 (Regular DP), HDCP Support : Yes
Power Consumption: Up to 300W additional 6+8 pin PCIe power required
Accessories: 1 x Power cable, Software, ASUS GPU Tweak & Driver
Dimensions: 27.17cm x 13.2cm x 4.06cm

Based on the same GK104 found on the GTX680, the GTX770 contains 1536 CUDA cores at a slightly higher clockspeed than the GTX680. The GTX770 comes in two varients, the 2GB and the 4GB version. For most the 2GB card will provide the best balance of power vs price however should you have a larger display, then the 4GB version may be worth opting for. Both versions feature a worlds first 7GBPs (GDDR5 effective)memory subsystem which is a significant boost over the GTX680. Comprising of the same 256-bit memory controller means the GTX770 has 224.3GB/sec memory bandwidth at it’s disposal.

Kepler Core
The GTX770 is equipped with a GK104 core is fabricated on the 28nm process with every component was designed with power efficiency in mind to ensure the GPU gave the best performance-per-watt possible.

While the 28nm manufacturing process holds the bulk of the power saving features, the way the new architecture works is also key to furthering Kepler’s power reduction. SMX, an evolution of the SM from Fermi is NVIDIA’s new streaming multiprocessor:

Each SMX runs at the graphics clock speed rather than 2x that speed as previously but because the GK104 has 1536 CUDA cores (8xSMX), over Fermi’s (GF110) 512 CUDA cores (16xSM), Kepler allows the GTX770 to operate at twice the performance per watt measurement compared to the GTX570.

The clock throughput of FMA2, SFU and texture operations have all been significantly increased and while some operations still retain the same speed as the GTX580, the GTX770’s much higher core clockspeed ensures a substantial increase for all GPU operations.

To feed the new SMX, each unit has four warp schedulers, each capable of firing off two instructions per warp, every clock. With a redesigned scheduling function, the GTX770 is a lot less complex and much more streamlined allowing the compiler to determine which instructions will be issued and can provide this information direct to the hardware block rather than going around the houses using Multi-port decode and a register scoreboard along with the dependency check before the information gets issued. This method is both quicker and more importantly, more power efficient.

Perhaps the biggest change from Fermi to Kepler was the omission of the old Shader Clock. The shader clock was getting tired as it was part of the old Tesla architecture which was implemented as an area optimisation. Because of the way Kepler executes instructions at a much more streamlined manner and at a higher clock rate, fewer copies of the execution unit need be made.

Another improvement over Fermi with the introduction of SMX is the redesigned Polymorph engine (2.0). The Polymorph engine takes card of the tessellation workload of the GTX770. The design of the Polymorph engine is to ensure that the tessellation we see on screen has little (as possible) impact on the rendering performance. What you may find bizarre though is that NVIDIA have cut the Polymorph engine count in half to 8 from Fermi’s 16 yet claim it is almost twice as quick. This is thanks to the improved core an memory clockpeed.

With both a higher core clockspeed based on older (but still very fast) GK104 core and of course that blisteringly fast memory, the GTX770 looks set to replace not only the GTX670, but it’s bigger, but older brother, last years flagship graphics card, the GTX680.

Features

DirectCU II with SSU architecture

20% cooler, 3X quieter

ASUS graphics card engineering leads the industry once again with the introduction of DirectCU II SSU thermal design. Comprising two “S” and one “U” shapes, the new heatpipes are precision shaped for optimal efficiency and heat transference. They are also nickel-plated to minimize oxidization, with their mid-section now placed directly over the GPU die. This design shortens heat transfer travel to lower thermal resistance and create bi-directional flow for up to twice the cooling capacity in the same space as that required by existing graphics card cooler designs. High-conductivity copper used in heatpipe formulation creates tube-like vapor chambers, moving heat to a large aluminum heatsink that features extended fins for multiple points of dissipation. The assembly is further chilled by two high performance but carefully-tuned and sound-dampened fans for faster and quieter cooling.

DIGI+ VRM with Super Alloy Power

30% less power noise and 2.5X greater durability

Acclaimed DIGI+ VRM has been applied via a 10-phase power design that uses digital voltage regulators to minimize power noise by 30%, enhance power efficiency by 15%, widen voltage modulation tolerance, and improve overall stability and longevity by 2.5 times over reference.

GPU Tweak

Real-time intuitive graphics tuning

Shows detailed specs and actual card status with GPU-Z
Monitoring widget provides real-time detailed multi-parameter info
Automatically checks and updates drivers and BIOS versions.

GPU Boost 2.0

GPU Boost caused a bit of a stir when it was first introduced because it did away with the traditional ‘absolute’ method of dictating MHz. Rather it worked by overclocking the card by different means. To achieve an overclock using GPU Boost, one increased the MHz and Voltage as per usual however the card would then ‘Boost’ when placed under load. So rather than having a fixed clockpseed, the GPU adjusts the clockspeed depending on load, ensuring the power is there when you need it rather than it being full on all of the time, thus saving power consumption and heat production by having the card overclock dynamically.

GPU Boost 2.0 is an evolution of this idea. The techs at NVIDIA have determined that GPU power was unnecessarily limiting performance when GPU temperatures was low. Instead of boosting GPU performance based on a power target, it is now based upon temperature with this temperature threshold being 80 degrees Celsius.

Because the boosting is now determined by temperature, noise levels are also reduced as NVIDIA claim the GTX cards deliver a better acoustic profile.

So to summarise, overclocking the card using GPU boost 2.0 means adjusting the temperature threshold, for example from 80c to 85c. The GPU clockspeed will then gradually increase until it reaches this new temperature and will be dynamically adjusted on-the-fly to stay within this threshold. Because of this it is much more difficult to claim one GPU is faster than another without having both working under precisely the same operating conditions.

It therefore should go without saying (but we will say it anyway) that the colder your card runs, the faster it should theoretically operate as a colder card allows overvolting and thus even higher clockspeeds.

GPU Boost 2.0 also features overvoltage control. NVIDIA make no bones that enabling this function will damage the long term operability of the graphics card and as with AMD’s overdrive, you have to acknowledge this fact before you can unlock the cards voltage control. We applaud NVIDIA for this because they have acknowledged that enthusiasts, like us here at Vortez, like to push hardware to the max and without voltage control, the whole process becomes so much more uninteresting and much more difficult.

So, because GTX770’s boost clock and voltage level are now tied to the GPU’s temperature, the voltage can be dialled higher which in turn will allow the GPU to attain higher clockspeed values. Obviously, increasingly board voltage, as with most other products, will gradually degrade the GPU through electron migration causing a premature death of the GPU. Voltage support will be offered on a board partner by partner basis however, we would be extremely surprised if it wasn’t enabled in every GTX770’s VBIOS.

We will see how GPU Boost 2.0 performs in our overclocking section later in the review.

GeForce Experience

GeForce Experience is a new application from NVIDIA that optimizes your PC in two key ways. First, it maximizes your game performance and game compatibility by automatically downloading the latest GeForce Game Ready drivers. Second, GeForce Experience intelligently optimizes graphics settings for all your favorite games based on your hardware configuration.

Some enthusiasts will view (excuse the pun) altering settings to get the very best from a game one of the ‘fun’ elements of owning a powerful graphics card. Others just want to play their game of choice without the endless testing and benchmarking to determine what settings work best. Many don’t have the inclination or indeed the time to learn what effect each setting has upon the games visual elements.It soon becomes a bind when upon a new driver release those settings which were great before can be bettered (or lowered) for a better gaming experience. FXAA, TSAA, MMAA or simply AA. Low, medium, high, ultra texture settings along with overall visual settings can be all too confusing when configuring a games visuals and while it would be easy to just crank everything up to maximum and hoping for the best, this all too often results in choppy, unplayable gaming ruining the gaming experience.

NVIDIA’s GeForce Experience removes much of the guess work when configuring a game thereby giving users the means to jump straight into the game with the best optimised settings for there hardware.

This handy utility will also keep your GPU updated with the latest driver that can be set to automatically download, ready to be installed as soon as they are available and also it gives you access to the beta drivers.

How does it work?
GeForce experience requires an internet connection which, once connected to the NVIDIA Cloud datacenter will download optimal game settings that are tailored to your PC based upon CPU, GPU and monitor resolution.

Low end hardware will have the visuals reduced to improve framerates while high end hardware will inevitably have higher settings assigned. This is all done with a click of a button which ensures that the game not only looks great but perhaps more importantly, plays smoothly.

Testing of the settings are done by NVIDIA themselves who benchmark the game, set a framerate target to ensure smooth gameplay then adjust the settings to ensure both framerate and smooth gameplay are optimised.

In our own tests, the utility worked well and is great for those who want to jump straight into the game with the minimal of fuss and furore of adjusting GPU settings.

Our one complaint is that the supported games list requires expanding. While most of the popular games are supported, many, especially some older but very popular titles are not.

Packaging & Accessories

The outer sleeve of the box features a small, fragmented diagram of the card on a backdrop of metal complete with ‘talon’ tears. Beneath this we find the main product features of DIGI+, GPU Tweak, 2GB GDDR5 and OC (Overclocked).

The rear of the package goes into greater detail regarding the features in multiple languages. ASUS also show the I/O backplate which is a nice addition.

Removing the sleeve we find a compartmentalised plain Matt black box, identical to their GPU range of the past two years. Not that this is a bad thing because this packaged, while hardly new, is one of the best out there ensuring that the product will reach you in perfect condition.

The accessory list is however less than appealing with just a single twin 6pin – 8pin PSU adaptor accompanying a driver/utility CD and quick start/installation guide.

First Look

The graphics card is dominated by the DirectCU II cooler. For those who already have a ROG board, this card will perfectly match the colour scheme thanks to the red highlights across the centre of the card adjacent to the twin fans.

The card features a backplate which is rare to see these days but very welcome nonetheless. The addition of this backplate makes the card much stronger, preventing unwanted bowing of the PCB under the cards own weight. It also serves to prevent damage by mishandling by protecting the otherwise exposed sensitive components beneath.

The backplate also features the name of the cooler, etched in gunmetal grey which gives the card an air of class about it, adding further to the visual appeal.

Things only get better with the profile of the card. Three heatpipes sprout from the midriff and stretch across the finned aluminium heatsink array which in turn is shielded by a matt black shroud. Our only complaint is that this makes the card slightly wider than the average sample measuring just shy of 13cm in width with the heatpipes included in this measurement.

Overall, the graphics card is a stunner to look at. We love the backplate and thanks to the matching matt black shroud, will look at home in almost any PC design.

Closer Look

The I/O area is NVIDIA reference featuring both DVI-I and DVI-D along with HDMI and DisplayPorts.

The twin fans direct air downward and outward over the heatsink and perform up to 6x better than reference design fans while being twice as quiet (ASUS).

As with all GTX770’s, the ASUS design features twin SLI tabs meaning it can be linked up with other cards from the same GTX770 family for multi-SLI gaming.

The power requirements of the GPU as stated on the packaging are 600W with 42A available on the 12v line. As you can see from the picture above, both 8 and 6pin PSU power cables are required for operation of this product.

ASUS have given the overclockers an extra monitoring tool by providing us with three voltage read points for the core, memory and PLL. We normally only see these on the flagship models so seeing them on this version is very welcome indeed.

Detailed Look

As with a few other manufacturers today, ASUS have taken the decision to prevent users from removing the heatsink without invalidating the warranty thanks to a small ‘screw seal’. For an enthusiast card which offers voltage monitoring via multimeter we find this an odd move to make overclocks taking advantage of this feature will add a waterblock or extreme cooling.

Regardless, we removed the heatsink via four spring loaded screws. The heatsink is stunning, comprising of 3 heatpipes that dissipate heat through the aluminium finned array.

DirectCU translated for those not familiar with the periodic table means the core comes into direct contact with the copper (Cu) heatpipes. The heatpipes are flattened at the baseplate but spring out, furnished with a layer of nickel coating across the heatsink. The contact area was very flat and while the paste was a little dry/chalky in consistency, the mount was very good.

The PCB is matt black, not that this is of any concern as you will be hard pushed to see it with both heatsink and backplate attached. The layout is fairly standard with the core being framed by the memory chips with VRM (separate heatsink attached) being closest to the power points for smooth, noise free power delivery.

The VRM is a ten phase power design comprising of Super Alloy Power components which translated means high quality solid state chokes and capacitors. The ten phase VRM will, ASUS claim, minimise power noise level by 30% and enhance power efficiency by 15%. This in turn should equate to enhanced overclocking stability.

Controlling the VRM is the DIGI+ ASP1212 voltage regulator.

The memory carries the product code of K4G20325FD-FC28 which are specified to run at 1750MHz (7000MHz GDDR5 effective). We know from experience that these little chips can be overclocked quite well!

Finally we reach the core of this VGA card. While the GK104 has been inherited from the 6XX family of GPU’s, a few tweaks by NVIDIA ensure that the beating heart of the GTX 770 is stronger than ever.

Test Setup

How we test graphics cards

Testing a graphics card is an extremely lengthy process. We sometimes see reviews where a graphic card has been tested using out of date equipment, out of date games and out of date drivers. While the latter can be excused due to the sheer amount of driver updates making a thorough review impossible we will however notify the reader when we have used a different driver to the normal for example a pre-release driver. For the most part however we will always use the same hardware and where possible the same drivers unless a newer driver rectifies an issue we have encountered or significantly improves performance to such an extent that continuing with an outdated driver is not feasible.

Frame Time Analysis
We have also seen the emergence of frame time analysis. We covered this in a separate article here: GPU Reviews: Why Frame Time Analysis is important so we won’t go into the reasoning again but to summarise, our testing comprises both FPS testing and perhaps arguably more importantly, frame time analysis. We also look at overall performance by equating averages across the games and finally before concluding our review we take a look at value for money.

HardwareWith the latest Intel chipset release we decided to update our ageing X58 setup to the new X79 chipset. Not only that but we will be using the flagship Core i7-3960X Extreme Edition processor clocked to 4.5GHz to ensure we have no CPU bottlenecks. With 16GB of ram on board there should be minimal paging so the benchmarks we run today will hopefully give a true reflection of the graphics card’s performance.

High End Graphics cards on test:

ASUS GTX770 DIRECT II CU OC 2GB GDDR5
(Forceware 320.49)
MSI GTX760 Twin Frozr Gaming 2GB GDDR5(Forceware 320.49)
GIGABYTE GTX780 Windforce x3 OC 3GB GDDR5(Forceware 320.49)
GAINWARD GTX780 PHANTOM ‘GLH’ 3GB GDDR5(Forceware 320.49)
INNO3D GTX760 ICHILL HERCULEZ 2GB GDDR5(Forceware 320.49)
GIGABYTE GTX770 WINDFORCE 3X OC 2GB GDDR5(Forceware 320.49)
ZOTAC GTX760 2GB GDDR5(Forceware 320.39)
NVIDIA GTX760 2GB GDDR5(Forceware 320.39)
]NVIDIA GTX760 2GB GDDR5 SLI(Forceware 320.39)
SAPPHIRE DUAL-X HD7950 3GB GDDR5 (Catalyst 13.6 beta)
CLUB 3D HD7970 royalAce 3GB GDDR5 (Catalyst 13.6 beta)
GAINWARD PHANTOM GTX 770 2GB GDDR5 (Forceware 320.18)
NVIDIA GeForce GTX 770 2GB GDDR5 (Forceware 320.18)
NVIDIA GeForce GTX 780 3GB GDDR5 (Forceware 320.18)
NVIDIA GeForce GTX 690 4GB GDDR5 (Forceware 314.22)
NVIDIA GeForce GTX TITAN 6GB GDDR5 (Forceware 314.22)
NVIDIA GeForce GTX TITAN SLI 12GB(2x6GB) GDDR5 (Forceware 314.22)
NVIDIA GTX680 2GB GDDR5 (Forceware 314.22)
AMD HD7970 3GB GDDR5 (AMD CAT 13.3 beta)

Motherboard: ASUS P9X79 Pro
CPU: Intel Core i7-3960X Extreme Edition @ 4.5GHz
RAM – 16GB (4x4GB) Corsair Vengeance (Red) DDR3 @ 1866MHz 9-10-9-27
Power Supply – Thortech Thunderbolt Plus 1200W
Hard Drive – Kingston HyperX 240GB
Cooler – Corsair H100

Benchmarks
If you are a regular reader of our reviews you will know we like to test the latest hardware with the latest games and benchmarks on the market. Here are the games we have chosen:

Battlefield 3
Crysis 3
Far Cry 3
BioShock Infinite
DiRT: Showdown
The Elder Scrolls: Skyrim

We also take into consideration the benchmarkers out there so have included 3 of the more popular synthetic benchmarks available:

Unigine: Valley
Unigine: Heaven 4
Futuremark 3DMark Firestrike

Let’s see how today’s graphics card performed…

Temperature, Acoustics and Power Consumption

Power Consumption

To test for power consumption we use the included iPower Meter found with our Thortech PSU. As system load figures obviously differ from idle it is extremely difficult to get an accurate figure of system draw and then simply take this figure away from the overall amount because each game will generate varying levels of CPU and hard drive activity. Dynamic power adjustments which fluctuate in game will also affect accurate power figures thus rendering any such power consumption calculations redundant at worst and approximate at best.

We will therefore take our system readings averaged over a benchmark run of Tessmark (100% load) and after 20 minutes of being idle in Windows 7. These can then be used as a comparison to other graphics cards to determine how much more or less power you can expect a GPU to consume.

Power consumption was on a par with the other GTX770s on test which is very respectable considering the factory overclock and twin cooling design.
Temperature

To test temperatures we measured idle temperatures after booting windows, letting all applications finish loading and ran a few benchmarks. Once the benchmarks were complete we left the card to reach a cooling plateau where we then took the idle temperatures. For the load tests, we would normally run Furmark for 20 minutes, taking the absolute maximum temperature attained however we found that this throttled the card and resulted in spurious results. So we set Heaven running continuously for 20 minutes and used this as a temperature result as the card did not throttle with this application.

The ASUS DirectCU II cooling certainly did its job here, being the coolest GTX770 on test.

Acoustics

While acoustic testing is subjective to one’s own hearing, you would have to have the hearing of a bat to complain about the noise the ASUS card makes because it was very quiet throughout our testing even when placed under load. Raising the fan manually to 100% obviously made the card more audible but not so bad that it couldn’t be tolerated for short periods of benchmarking.

Let’s see how the card performs in our suite of benchmarks…

Futuremark 3DMark Fire Strike (Synthetic)

Fire Strike is the new showcase DirectX 11 benchmark designed for high-performance gaming PCs. It is Futuremark’s most ambitious and technical benchmark ever, featuring real-time graphics rendered with detail and complexity far beyond what is found in other benchmarks and games today.

Unigine: Heaven 4 (Synthetic)

Heaven Benchmark with its current version 4.0 is a GPU-intensive benchmark that hammers graphics cards to the limits. This powerful tool can be effectively used to determine the stability of a GPU under extremely stressful conditions, as well as check the cooling system’s potential under maximum heat output. It provides completely unbiased results and generates true in-game rendering workloads across all platforms.

Unigine: Valley (Synthetic)

Valley Benchmark is a new GPU stress-testing tool from the developers of the very popular and highly acclaimed Heaven Benchmark. The forest-covered valley surrounded by vast mountains amazes with its scale from a bird’s-eye view and is extremely detailed down to every leaf and flower petal. This non-synthetic benchmark powered by the state-of-the art UNIGINE Engine showcases a comprehensive set of cutting-edge graphics technologies with a dynamic environment and fully interactive modes available to the end user.

Battlefield 3 (FPS)

Battlefield 3 leaps ahead of its time with the power of Frostbite™ 2, the next installment of DICE’s cutting-edge game engine. This state-of-the-art technology is the foundation on which Battlefield 3 is built, delivering enhanced visual quality, a grand sense of scale, massive destruction, dynamic audio and incredibly lifelike character animations. As bullets whiz by, walls crumble, and explosions throw you to the ground, the battlefield feels more alive and interactive than ever before. In Battlefield 3, players step into the role of the elite U.S. Marines where they will experience heart-pounding missions across diverse locations including Paris, Tehran and New York.

Average and minimum frames per second were measured using Fraps during the parking lot scene on Operation Sword Breaker. High and Ultra presets were loaded at both resolutions.

Crysis 3 (FPS)

Crysis 3 from Electronic Arts is the fourth instalment of the Crysis franchise and sequel to Crysis 2. It uses the CryEngine 3 gaming engine which is perhaps the most advanced gaming engine to date and therefore the most demanding. The meme ‘Can it run Crysis’ has never been so apparent…

Far Cry 3 (FPS)

Far Cry 3 is a tropical survival shooter video game from Ubisoft Montreal and Massive studios. It’s open world design has similar traits to it’s forbear Far Cry 2 but it does it all so much better. With stunning visuals and settings to bring a PC to it’s knee’s, this game is so much more than the ‘just another console port’ it was reported to be.

BioShock Infinite (FPS)

Set in 1912 during the growth of American exceptionalism, BioShock Infinite is a thrid person shooter developed by Irrational games and published by 2K Games. It is the third instalment of the BioShock franchise. the game utilises the Unreal Engine 3, modifying it with their own lighting engine to present a visually stunning experience like no other.

DiRT: Showdown (FPS)

DiRT Showdown is the new arcade racing game from the team that brought you the award-winning DiRT series, uncaged in 2012. Pick up and play controls combine with electrifying events, frenzied crowds and stunning graphics to deliver high octane, dive in and drive thrills from event one.

The Elder Scrolls: Skyrim (FPS)

Skyrim is not a direct successor to the very popular Oblivion. Instead it takes place 200 years after the events of Oblivion. The non-linear playing that made the Elder Scrolls such a popular series does however make a return along with the beautiful scenery the encompasses the world of Skyrim.

Average and minimum frames per second were measured using Fraps during the drop down passage to Riverwood. V-sync was disabled to allow fluctuating (higher the 60) FPS for these runs. It is however recommended that v-sync is left enabled during normal gameplay due to the games dynamics.

Gaming Experience (Frame Time Analysis)

Here we take a look at both average (black) and 99th Percentile (coloured) response times of the graphics cards. It is highly unlikely a user will notice any micro stutter (also incorrectly referred to as lag but the effect can be interpreted to be similar) at anything below 30ms but every gamers perception differs.

Comment

The graphs above may appear very daunting however, what you want to see is a smooth line (not fuzzy) with very few peaks and troughs. While you are unlikely to notice peaks and troughs below 30ms, any peak above 30ms may be seen as a stutter during gameplay. This will however depend greatly on your own perceptions. Multi card setups are more likely to show frame lag due to the nature of cross communicating to render frames.

Average and 99th Percentile response times (Frame Time Analysis)

Value For Money

We make a simple calculation for this set of results. For each game we add all of the resulting FPS totals together and then divide by the four sets to give us an overall performance figure. While the figures alone do not give you an accurate picture of how the card will perform in any given scenario, they do tell you, when averaged, which GPU is the more capable across all of the benchmarks and settings tested.

Overclocking (GPU BOOST 2.0)

For overclocking our NVIDIA cards we will be using EVGA’s Precision too (ver. 4.1) as this gives us all of the options we require. Should you desire, ASUS’ own GPU Tweak is equally good.

Above is a screenshot of GPU-Z showing the reference (factory overclocked) speeds and reference boost clocks. We do wonder why ASUS were so conservative with the factory overclocks, especially when you consider direct competitors to ASUS have cards clocked much higher for around the same price. That said with a lower factory overclock, there is likely to be more left in the tank for us to extract…

Overclocking a card which is already overclocked from the factory usually limits the amount of overclocking headroom remaining. Regardless, we managed to push the ASUS card a little further resulting in an additional 135MHz on the core. This gave us a blistering boost 2.0 speed of 1293MHz – quite astonishing! Couple this with the average but no less impressive 550MHz overclock on the memory and this card will undoubtedly satisfy even the most fastidious of overclockers.

After settling on our stable clockspeed which was verified by multiple runs of Unigine Heaven and 3DMark we benchmarked the overclock and compared it to stock results with Unigine Heaven 4.0 to evaluate the benefits of overclocking the GPU.

Conclusion

It’s been a while since we had the pleasure of reviewing an ASUS GPU here at Vortez so when the GTX770 DirectCU II OC landed on the office desk we were eager to see what ASUS had in store for us. We were not disappointed.

To begin with, the card is great to look at. The aesthetics are sublime throughout thanks to the understated Matt black colouration. With only a hint of red, the card will appeal to all but particularly those who have a ROG motherboard. We were grateful for the backplate which adds massively to the looks of the card once installed and perhaps more importantly, protects the card from damage be it a dropped screw creating a short circuit or static discharge.

Stripping the card back to the PCB we saw that the excellent engineering was not only skin deep. The DirectCU II cooler, while not exactly ground breaking in design, performed extremely well so the design cannot be faulted by us at all. It ran cooler than the TITAN-esque reference design which is no easy task and thus testament to the excellent cooling properties of DirectCU II.

Overclockers will be happy with the features the card provides however we were a little perturbed to see a seal atop of a screw head preventing heatsink removal without invalidating the warranty. That aside, the card did overclock well although the factory overclock was very conservative compared to factory overclocked competitor models which was a shame.

The ASUS GTX770 DirectCU OC is priced competitively at around £340 which is an average price for a GTX770. ASUS usually carry a slight premium and because of the DirectCU II cooler we expected this card to be more expensive so while it isn’t an absolute steal, it is not overly expensive either. There are competitor cards however which weigh in at a similar price but carry a faster factory overclock which is perhaps the only chink in the ASUS armour we can find. Were it clocked higher than the competition we could have had a ‘Platinum award winner but alas, the ASUS GTX770 DirectCU II OC will have to settle for our esteemed and very respectable Gold award.

To summarise:
If you are looking for a high end GPU that ticks all the right boxes, we highly recommend you take a long hard look at the ASUS GTX770 DirectCU OC because not only is it cool and quiet, it’s also scorchingly fast.

Pros
+ Good Overclocking features
+ Great cooling ability
+ Factory overclocked
+ Fantastic looks
+ Competitive price

Cons
– Warranty void if heatsink removed
– Some competitors are faster at reference clockspeeds
– Disproportionately high latency in DiRT Showdown and Skyrim games