Fractal Design Kelvin S24 Review
Published: 9th January 2015 | Source: Fractal Design | Price: TBC |
Performance and Testing
The test set up consisted of the following
Intel i7 3960X [email protected] 1.1v (undervolted) 4.0GHz @ 1.25v 4.4GHz @ 1.35v 4.6GHz @ 1.45v Gigabyte X79 UD3 Corsair Vengeance LP Memory Corsair HX850 V2 Corsair Force GT 60GB Coolermaster Storm Trooper.
The graphs are now in jpeg format for all the mobile device users out there and are placed in order with the best performing at the top so as to help better visualise where the cooler we're testing comes in the pack.
As usual we'll be testing our coolers at varying levels of overclock and increasing levels of voltage. This in turn of course means increasing levels of heat which the coolers need to dissipate. To begin with we start with the undervolted stock speed. Why undervolted? well if you have things set on "Auto", you may well be using more volts than are actually required to run at the chosen frequency, for example our 3960s will run quite happily at just 1.1volts, solid as a rock, 24/7, and as such we use this as our starting point.
Continuity is very important in testing, and for this reason we keep as many of the potential variables as locked down as possible. We will be using OCCT in Linpack X64, AVX compatible with all logical cores tested and 90% free memory utilised. The test is set up to run automatically with just a few clicks to set it going. A 10 minute idle followed by 30 minutes of testing and a 5 minute cool down is the order of the day and brings the total test time per clock speed to 45 minutes. So as to remove subjectivity in determining whether a CPU has failed, OCCT is set to stop the test and register a fail should the max temp exceed 80 degrees. In testing we noted that if even just one of the cores exceeds 82 degrees OCCT halts the test and a fail is recorded.
OK, so not the greatest start in the world. The S24 is quite low down the charts when compared to other 240mm units.
Turning now to the 4GHz test we up the voltage to 1.25 volts, this is what is deemed normally as stock volts. Something we are always harping on about on the forums is AUTO does not mean stock volts, and normally if you overclocking with "auto" volts the motherboard will be upping the volts much more than needed if you were to do it manually. By whichever means it happens, upping the volts (especially from our 1.1v undervolt) does have a big impact on temps, with an average increase of 10-15 degrees seen in the results.
At the higher levels of heat generated by the increase in voltage required for the 4.0GHz overclock, fan performance, although still a factor becomes less critical, replaced instead by a coolers ability to conduct the heat up the heat pipes and more crucially the total surface area of the fins enabling convection to the atmosphere. In the case of AIOs and water cooling the surface area of the radiator and the efficiency of the contact plate begin to play more of a role.
Aside from the Nepton the S24 is now nearing the bottom of the 240mm based units. The extra heat generated by this mild overclock seems to causing it o heat up a bit.
Upping the volts still further we achieve a stable 4.4GHz overclock at 1.35 Volts. It's here we start to separate the wheat from the chaff, with lesser coolers not able to disperse the increased heat effectively. Again we see a jump of 10 degrees or so from the figures at 4GHz. Both the H100 and the well-respected D14 are creeping into the 70s here, indicating that only the cream of the crop will excel at this level.
At 4.4GHz the position of the S24 relative to the other coolers remains un changed. It might not be ripping the arse out of the charts but it's still in there.
Only the most effective coolers are capable of making it into the hallowed 4.6GHz club and as you can see in the graph below there isn't a single air cooler in this graph, even the NH-D14 does not have enough cooling potential to be featured here. So all that has made this graph so far are the AIO big players and dedicated custom watercooling kits.
We didn't think for a moment that the S24 wouldn't make it into the top tier 4.6GHz group, but as testing progressed we did have our suspicions that it would be near the bottom. However at the end of the day the S24 has a few things the othesr don't that will see its overall performance score raised