Noctua NH-C14S and NH-D15S Review
Published: 24th July 2015 | Source: Noctua | Price: £65.75 and £60.19 |
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.
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.
Interestingly the D15S is only 0.6 of a degree off the pace of the full fat twin fan version, but rather worryingly the C14S is well down the rankings.
These low volt low overclocks are not where the action's at though and aren't that much of an indicator as to how well a cooler will cope once the volts have been cranked up, so let's wind things up a bit.
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 factor.
Again we see the D15S is only just off the pace of the D15 with the next best cooler that isn't a Noctua being the bequiet Dark Rock Pro3, which is a good 4.5 degrees off the pace. Looking at the performance of the C14S you might think it's pretty crappy. OK so it's not doing as well as it's big brother, but look at the coolers below it, realising that the majority of those are full tower designs and you might think again. That said, the Dark Rock TF we reviewed recently is 4 degrees cooler and it shares a similar design.
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. This is where we start to separate the men from the boys.
As expected the C14S has dropped off the bottom, but the D15S is still going strong. taking second place in the charts with regards to air coolers and beaten only by the mighty D15, and then by only half a degree.