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Review: Fractal Design Kelvin S24

by Parm Mann on 9 December 2014, 12:00

Tags: Fractal Design

Quick Link: HEXUS.net/qacmgn

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Specification and Test Methodology

To put CPU cooler performance into perspective we're benchmarking using a high-end Intel Haswell test platform. A detailed description of the CPU cooler being reviewed, our test platform and all comparison coolers can be found in the tables below.

Fractal Design Kelvin S24 Specification

Socket compatibility Intel: 775, 1150, 1155, 1156, 1366, 2011
AMD: AM2, AM2+, AM3, AM3+, FM1, FM2, FM2+
General Specifications Block/pump assembly measurements: 69*69*40mm
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"
Fans included: 2
Fractal Design Zero™ Thermal Paste ; 1g syringe, sufficient for multiple mountings
Colours Available: Black
Net weight - Base unit only, not including mounting or fans: 1.2kg
Net weight - SS-HP fan, per fan: 165g
Package dimensions - W x H x D: 350*250*151mm
Package weight: 2.5kg
Fan Specification Fractal Design Silent Series HP 120mm
800 - 1700RPM
PWM control
Max air flow: 62.4CFM
Max pressure: 2.33mm H2O
Acoustical noise: 26.9dB(A)
DC 12V, 0.18A
Pump Specification Ceramic bearing
Voltage control
Maximum water flow: 72 l/h
Maximum pressure: 1.0m H2O
Acoustical noise: 25.0dB(A)
DC 12V, 0.27A
Package Contents Fractal Design Kelvin S24 pre-assembled Water Cooling Unit
2 Fractal Design Silent Series HP PWM controlled fans
Intel 775,1150,1155,1156,1366 mounting hardware (including back plate)
Intel 2011 mounting hardware
AMD AM2,AM2+,AM3,AM3+,FM1,FM2,FM2+ mounting hardware
PWM splitter cable
Fractal Design Zero™ Thermal Paste, 1g Syringe
Long and short radiator mounting screws
User manual

HEXUS CPU Cooler Test Bench

Hardware Components HEXUS Review Product Page
Processor Intel Core i7-4770K (quad-core, overclocked up to 4.40GHz) June 2013 Intel.com
Motherboard Asus Z97-A May 2014 Asus.com
Memory 16GB Corsair Vengeance Pro (2x8GB) DDR3 @ 1,866MHz - Corsair.com
Graphics Card Nvidia GeForce GTX Titan (6GB) February 2013 GeForce.com
Power Supply Corsair AX760i - Corsair.com
Storage Device Crucial M500 240GB SSD July 2013 Crucial.com
Chassis Corsair Graphite Series 600T October 2010 Corsair.com
Monitor Philips Brilliance 4K Ultra HD LED (288P6LJEB/00) - Philips.co.uk
Operating system Windows 8.1 (64-bit) October 2012 Microsoft.com

Comparison Coolers

  Fan(s) Fan speed Radiator dimensions Heatsink dimensions (inc. fans) Warranty
Zalman LQ315 1x Zalman ZP1225ALM 120mm 900 RPM - 2,000 RPM Width: 120mm
Height: 153mm
Depth: 38mm
- 2 Years
Fractal Design Kelvin S24 2x Fractal Design Silent Series HP 120mm 800 RPM - 1,700 RPM Width: 275mm
Height: 124mm
Depth: 33mm
- 2 Years
Intel Reference E97378-001 1x Intel PWM 92mm 1,200 RPM - 2,800 RPM - Height: 50mm
Width: 92mm
Depth: 92mm
1 Year
Noctua NH-D15 2x Noctua NF/-A15 140mm 300 RPM - 1,500 RPM - Height: 165mm
Width: 150mm
Depth: 161mm
6 Years

Benchmark Process

To get a feel for how the above coolers compare, we run our Core i7-4770K processor overclocked to 4.4GHz. In order to push the coolers, voltage is upped to an above-average 1.2V and memory operates at 1,866MHz using the built-in XMP profile.

Temperature is logged while a large 4K video clip is encoded using the freeware HandBrake utility. The workload tasks all four cores/eight threads, and in order to provide a stabilised reading, we then calculate the average temperature across all four cores from the last few minutes of encoding.

Actual CPU temperature is recorded, but to take into account any fluctuations in our lab, we also graph the delta temperature - that's CPU temperature minus ambient temperature. And, last but not least, to give you an idea of cooler acoustics, we use a PCE-318 noise meter to measure overall system noise in both idle and load states.


Our Corsair Graphite Series 600T chassis is set to run with three installed fans; a 200mm Corsair front intake; a 200mm Corsair top exhaust; and a 140mm Noctua NH-A15 rear exhaust. The front and top fans are configured to run quietly using a custom DC profile from within the Asus BIOS, while the rear exhaust and CPU cooler are set to the 'standard' PWM profile. Where necessary, any of the three aforementioned fans are removed to make way for radiator installations.

Any fans connected to a radiator are configured per the manufacturer's recommendations. If none are made, fans are set to draw air in from outside the chassis (thereby ensuring that the delta between the air temperature and the temperature of the radiator is maximised).

The Fractal Design Kelvin S24 is the second cooler to be tested on our new Intel Core i7-4770K test platform. For comparison, we've included benchmark results from the Intel reference cooler, a high-end Noctua NH-D15 air cooler and a Zalman LQ315 liquid cooler.