Fractal Design enter the water cooling market with the Kelvin Series liquid CPU coolers. We test out the S24 – 240mm radiator model.
Product on Review: Kelvin S24 Performance Cooler
Manufacturer: Fractal Design
Street Price: £89 GBP / $120 USD
Known for their passion with elegant case manufacture and silence, Fractal Design have expanded into the water cooling market by developing a new series of all-in-one liquid cooling solutions. Available in three different sizes, the Kelvin series offers 120, 240 and 360mm radiator models for enthusiasts to make use of.
Kelvin S24 is a closed loop liquid cooling solution which utilises a 240mm radiator. As such Fractal Design include dual 120mm cooling fans which are operate up to 1700RPM – slightly unusual for a product of this calibre which would usually have the facility of up to 2500RPM from other rivals.
Join us as we explore this new product and reveal what you can expect from its performance.
Fractal Design on their Kelvin S24
Simple to install, silent operation, powerful performance and easy expandability define the Kelvin Series. The silent high-performance ceramic pump is strong enough to support considerable expansion, should you decide to include GPU blocks and/or additional radiators in the same loop.
The Kelvin Series water cooling systems are constructed from enthusiast class components. Both the CPU block and the radiator are made from pure copper, for maximum performance and an increased product life span with zero maintenance required.
All modern CPU sockets are supported by the versatile, easy-to-use mounting kit.
The Kelvin Series water cooling systems are constructed from enthusiast class components. Both the CPU block and the radiator are made from pure copper, for maximum performance and an increased product life span with zero maintenance required.
All modern CPU sockets are supported by the versatile, easy-to-use mounting kit.
Technical Specifications
General Specifications
Block/pump assembly measurements: 69*69*40 mm
Tubing Measurements: 320mm long, 11mm outer and 8mm inner diameter
Fitted with anti-kink coils for worry-free installation
Kelvin S24 Radiator Measurements: 30*124*275mm
Thread class for fill port and all tube fittings: G 1/4″
Supported sockets: Intel: 775,1150,1155,1156,1366,2011; AMD: AM2,AM2+,AM3,AM3+,FM1,FM2,FM2+
Fans included: 2 pcs
Fractal Design Zero™ Thermal Paste ; 1 g syringe, sufficient for multiple mountings
Colors Available: Black
Net weight – Base unit only, not including mounting or fans: 1.2 kg
Net weight – SS-HP fan, per fan: 165 g
Net weight – Total excluding packaging and manual. Includes fans, mounting kit for all platforms, cooling paste (including packaging for the cooling paste) and adapter cable: 1.8 kg
Package dimensions – W x H x D: 350*250*151 mm
Package weight: 2.5 kg
Fan Specification
Fractal Design Silent Series HP 120 mm
800 – 1700 RPM
PWM control
Max air flow: 62.4 CFM
Max pressure: 2.33 mm H2O
Acoustical noise: 26.9 dB(A)
DC 12V, 0.18A
Pump Specification
Ceramic bearing
2400 RPM
Voltage control
Maximum water flow: 72 l/h
Maximum pressure: 1.0 m H2O
Acoustical noise: 25.0 dB(A)
DC 12V, 0.27A
Block/pump assembly measurements: 69*69*40 mm
Tubing Measurements: 320mm long, 11mm outer and 8mm inner diameter
Fitted with anti-kink coils for worry-free installation
Kelvin S24 Radiator Measurements: 30*124*275mm
Thread class for fill port and all tube fittings: G 1/4″
Supported sockets: Intel: 775,1150,1155,1156,1366,2011; AMD: AM2,AM2+,AM3,AM3+,FM1,FM2,FM2+
Fans included: 2 pcs
Fractal Design Zero™ Thermal Paste ; 1 g syringe, sufficient for multiple mountings
Colors Available: Black
Net weight – Base unit only, not including mounting or fans: 1.2 kg
Net weight – SS-HP fan, per fan: 165 g
Net weight – Total excluding packaging and manual. Includes fans, mounting kit for all platforms, cooling paste (including packaging for the cooling paste) and adapter cable: 1.8 kg
Package dimensions – W x H x D: 350*250*151 mm
Package weight: 2.5 kg
Fan Specification
Fractal Design Silent Series HP 120 mm
800 – 1700 RPM
PWM control
Max air flow: 62.4 CFM
Max pressure: 2.33 mm H2O
Acoustical noise: 26.9 dB(A)
DC 12V, 0.18A
Pump Specification
Ceramic bearing
2400 RPM
Voltage control
Maximum water flow: 72 l/h
Maximum pressure: 1.0 m H2O
Acoustical noise: 25.0 dB(A)
DC 12V, 0.27A
Packaging & Bundle
Packaging for Kelvin S24
Arriving in a large box, S24 has been given minimalist and professional styling. There are various illustrations of the cooler on front and sides, along with a detailed run-down of the features and specifications.
Inside the box
Opening the box up, all of the components are covered in plastic packaging and well-protected with a cardboard mould.
Mounting kit for AMD and Intel sockets
Kelvin S24 can be installed on multiple sockets to include:
Intel: 775,1150,1155,1156,1366,2011
AMD: AM2,AM2+,AM3,AM3+,FM1,FM2,FM2+
There are also an assortment of items included with the cooler to assist with installing it. The following components are included:
• Mounting kit for AMD/Intel sockets
• Instructions guide
• Fractal Design Zero thermal paste
• Y-cable (2-in-1 fan adapter)
Dual 120mm cooling fans included
Additional to the mounting kit are two 120mm cooling fans – Silent Series HP. These fans are designed to provide high-pressure and are PWM ready, supplying 800-1700RPM.
Closer Look
S24 uses a 240mm radiator
The Kelvin series is available in a variety of different sizes but as the S24 denotes, this product comes with a 240mm radiator to work in conjunction with dual 120mm cooling fans. The radiator is fully copper and measures 3 x 12.4 x 27.5cm, it can therefore fit at the top of most conventional computer cases.
It’s worth noting that the Kelvin series has been designed in collaboration with Alphacool who are regarded as experts in the field of liquid cooling.
Stiff plastic tubing with brass fittings
Being a liquid cooler means there is already fluid inside the tubes/radiator. The tubes which link between the pump and radiator allow this liquid to flow to and from by connecting to compartments within the radiator. Liquid flows into one and out of the other once it has cycled through the entire radiator.
The tubes are unlike most other closed loop solutions which opt for soft rubber – instead we have two stiff plastic tubes, but thankfully they are flexible due to the expandable two-part brass fittings.
Fractal Design has given the option to re-fill the unit should this be required.
Attractive, minimalist pump
The pump itself features the Fractal Design logo which sits on a glossy plastic shell. The specifications for this pump include: ceramic bearing 2400 RPM, acoustical noise: 25.0 dB(A) – the unit is powered via a 3-pin header.
Copper baseplate on the underside
Flipping the pump over we have a square copper baseplate and unlike other all-in-one solutions, S24 doesn’t come with a pre-applied helping of thermal paste – this needs to be applied independently.
Installation Process
In order to demonstrate the installation process for Kelvin S24 we are installing the cooler on the Intel LGA2011 socket.
STEP 1
Two brackets need to be fitted to the indentations on the pump.
STEP 2
The brackets do not have any pre-applied screws which does hinder the installation process somewhat. A screw, spring, washer and nut needs to be placed between each ring on the bracket manually.
STEP 03
The radiator and fans must now be fitted to the computer chassis. There is usually a dual fan location at the top – in our Corsair 500R we have a small cavity on the outside to which the radiator can sit. Unfortunately the radiator and fans cannot both sit inside the chassis because the motherboard prohibits this – the heatsinks touch the fans.
One extremely cumbersome feature about this step is that the screws require an allen key to tighten up. Trying to line up the radiator, fans, and screws… and turn an allen key all at the same time is ridiculously difficult and after plenty of wasted time we had to loan a screwdriver with this attachment fitted in order to get the job done. Fractal Design didn’t need to break out of traditional with the screws – it only makes the job troublesome.
STEP 04
The final step is to line up the screws with the mounting holes on the socket and tighten up with a screwdriver. Again, this can be tricky because each screw is variable and can move 2cm backwards or forwards – they don’t snap into place.
It’s advisable to tighten screws a few turns in a diagonal fashion to apply event pressure to the pump.
Overall the installation is somewhat tedious – we’d like to see the process more streamlined and less prone to hitting obstacles which we’ve mentioned above.
Test Setup & Methodology
Test System
CPU – Intel Core i7-3930K (3.6GHz)
Motherboard – GIGABYTE X79-UP4
Memory – 8GB Corsair Vengeance LP 1600MHz CL9
Graphics – Sapphire Radeon HD 6850 1GB
PSU – NZXT Hale90 650W
Hard Drive – Kingston HyperX 240GB SATA III SSD
Case – Corsair Carbide 500R White
Motherboard – GIGABYTE X79-UP4
Memory – 8GB Corsair Vengeance LP 1600MHz CL9
Graphics – Sapphire Radeon HD 6850 1GB
PSU – NZXT Hale90 650W
Hard Drive – Kingston HyperX 240GB SATA III SSD
Case – Corsair Carbide 500R White
CPU Coolers
Alpenföhn Matterhorn Pure(120mm Wingboost: 300-1200RPM)
Alpenföhn K2 (120mm Wingboost: 500-1500RPM, 140mm Wingboost: 300-1100RPM)
Alpenföhn Gotthard (140mm Wingboost: 300-1100RPM)
Noctua NH-D14 (120mm NF-P12 PWM + 140mm NF-P14 PWM: up to 1200RPM)
Thermalright SilverArrow SB-E Extreme (Dual TY-143 fans – 600-2500RPM)
Corsair Hydro H100 (Dual 120mm fans – low: 1300RPM, mid: 2000RPM, high: 2600RPM Push Config)
SilverStone HE01 (140mm PWM fan – 500RPM-1200RPM – 500RPM-2000RPM)
be quiet! Dark Rock Pro 2 (135mm + 120mm PWM Fans – up to 1500RPM and 1700RPM)
Thermaltake Water 2.0 Pro (Dual 120mm PWM fans – up to 2000RPM)
Corsair Hydro Series H100i (Dual 120mm fans – up to 2700RPM Push Config)
Be Quiet! Shadow Rock TopFlow(1x 135mm PWM fan – up to 1500RPM)
SilverStone HE02 (Passive – optional fan used: Noctua NF-F12 120mm PWM)
Corsair H55 (Single 120mm fan – 1700RPM Exhaust Push)
Cooler Master Seidon 120M (Single 120mm fan – Up to 2500RPM Exhaust Push)
Zalman CNPS11X Extreme (Single 120mm fan – Up to 1950RPM)
Phanteks PH-TC12DX (Dual 120mm fans – 600-1800RPM)
Noctua NH-U14S (Single 140mm cooling fan – 300-1500RPM)
SilverStone TD03 (Dual 120mm fans – 1500-2500RPM)
Thermaltake]Thermaltake NiC C5 (Dual 120mm fans – 1000RPM – 2000RPM)
Raijintek EreBoss (Single 140mm fan – 1100RPM – 1600RPM)
GamerStorm Lucifer (Single 140mm fan – 800-1500RPM)
Cooler Master V8 GTS (Dual 140mm fans – 600-1600RPM)
Antec KUHLER H2O 1250 (Dual 120mm cooling fans – 600-2400RPM)
Corsair H75 (Dual 120mm cooling fans – 600-2000RPM)
CRYORIG R1 Ultimate (Dual 140mm cooling fans – 700-1400RPM)
Corsair Hydro Series H105 – (Dual 120mm fans – up to 2700RPM Push Config)
Noctua NH-D15 (Dual 140mm cooling fans – 300-1500RPM)
LEPA LV12 (Single 120mm cooling fan – 300-2200RPM)
CRYORIG H5 Universal (Single 140mm cooling fan – 600-1400RPM)
Fractal Design Kelvin S24 (Dual 120mm cooling fans – 800-1700RPM)
Program Suite
Real Temp – Maximum temperature analysis
LinX 0.6.4 – Applies thorough stress test to CPU
CPU-Z – Confirmation of CPU frequency/voltage
AIDA64 Extreme Edition – Confirmation of temperatures/fan speeds
Testing methodology
Testing will be based on temperatures recorded by Real Temp after 20 passes of LinX stress test. The maximum absolute temperatures will be recorded after the test and averaged over the 6 cores. The delta is then calculated by subtracting the temperature recorded near the intake fans from the average temperature calculated. Tests are conducted with the Intel i7 3930K at its default 3.6GHz stock speed and overclocked to 4.6GHz @ 1.42V. The tests are done inside the Corsair Carbide 500R chassis to simulate real world conditions. To keep the tests standardised we are using Noctua’s NT-H1 thermal paste on all coolers.
CPU coolers are reviewed as they come out of the box – with their factory cooling fans, as the manufacturer intended and as the consumer expects.
Additional tests include a passive test where the cooling fans are taken away from the heatsink and a comparison between the cooler used with stock thermal paste against our Noctua NT-H1 paste.
A kind thank you to Noctua for supplying us with NT-H1 thermal compound.
Results – Stock Performance
Using Kelvin S24 with stock settings applied to the CPU presents us with some good performance results.
Fan Speed: Both fans remained at 1200-1300RPM throughout stock testing – noise is only just noticeable.
Results – Overclocked Performance
Stepping things up by applying a substantial overclock to the CPU means that Kelvin S24 does struggle somewhat. We suggest that a 200RPM cooling fan could possibly improve the temperatures here.
Fan Speed: Both fans maxed out at 1700RPM during overclocked testing – noise is now noticeable but tolerable.
Results – Passive Performance
As can be expected from a liquid cooling which relies upon cooling fans to disperse heat, Kelvin S24 struggled in the passive testing. Other all-in-one solutions experience the same difficulties so this comes as no surprise.
Results – Thermal Paste Comparison
Most CPU coolers come accompanied with thermal paste provided by the manufacturer. For our CPU cooling tests we use Noctua’s NT-H1, so to offer up some interesting analysis we test the thermal paste given with Kelvin S24 against NT-H1 to see which gives the best results during stock and overclocked performance and the results really aren’t that much different at all. Fractal Design has done a great job in producing this competitive thermal paste.
Conclusion
After plenty of success with their cases, case fans and power supplies, it’s only natural for Fractal Design to extend into even more cooling solutions. The new Kelvin series has its work cut-out in the field of all-in-one liquid coolers because a number of critically acclaimed products are already well-established.
Fractal Design has done a great job in ensuring the bundle for the S24 covers all eventualities – this cooler can accommodate multiple sockets from Intel and AMD and comes with a full tubed of thermal paste. Build quality is also something which resonates throughout this product, to all components.
Performance is likely to be the topic most enthusiasts will be seeking out and certainly for the stock performance the Kelvin S24 did a reasonable job. Comparing it to other 240mm liquid coolers, the S24 does drop behind the pack somewhat and there are a number of air coolers which cost half the price but offer similar performance. The bonus with opting for a closed loop solution like S24 over an air cooler is that there is much more space around the CPU socket to avoid obstructions for components such as tall memory modules. Throughout our testing we applied a significant overclock to the CPU but unfortunately S24 dropped further back in the cooling league and struggled to affectively cool the chip.
We appreciate this is Fractal Design’s first attempt at designing such a product but we feel they could make some improvements – streamlining the installation process is certainly something we’d like to see. Breaking out of tradition they have included screws which require allen keys to tighten, which only adds frustration when trying to balance and lineup the radiator, fans, screw holes. Furthermore, there are no retention screws pre-fixed. Springs, screws, washers all have to be aligned to the brackets.
At a cost of £89 GBP / $120 USD the Kelvin S24 is placed accurately among other 240mm coolers but the competition is rather fierce.
The Kelvin S24 is a good first attempt at water cooling for Fractal Design, but it isn’t without its flaws.
Pros
+ Good bundle
+ Generous clearance around socket for memory
+ Pleasing build quality/aesthetics
+ Multi-socket support
Cons
– Awkward to install
– Struggles when substantial overclock applied
+ Good bundle
+ Generous clearance around socket for memory
+ Pleasing build quality/aesthetics
+ Multi-socket support
Cons
– Awkward to install
– Struggles when substantial overclock applied
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