Here are the results of our cooling performance tests, plotted over time:
And here are the minimum and maximum numbers from each of our testing phases:
Something about our test rig causes it to report CPU idle temperatures below the ambient conditions of our testing environment. Since the Wraith isn't a Peltier cooler, that seems unlikely. I don't have a spare Socket AM3+ motherboard to cross-check against our Gigabyte mobo, so feel free to ignore our idle temperature numbers and just concentrate on the load figures.
Even with the rather restrictive custom fan curve I created, the Wraith delivers impressive cooling results atop a stock-clocked FX-8370. The processor's load temps topped out at 69° C under our grueling Prime95 Small FFTs load. To get there, the Wraith only had to spin its fan at a reported 1321 RPM, less than half of its roughly 3000-RPM rated maximum. Using a similar fan curve, the Hyper D92 shaved only three degrees C off the Wraith's load number. Not bad for a stock heatsink cooling a 125W CPU.
For those willing to tolerate more noise, the Wraith's fan still has plenty of room to stretch its legs if those temperatures are worrisome. It might even be possible to eke a mild overclock out of the FX-8370 with the Wraith if noise levels aren't a concern. The Hyper D92 has even more headroom still, considering it's a larger tower-style cooler with dual fans. It's worth remembering that the Cooler Master heatsink is a $45 extra, though, while builders will get the Wraith in the box with the FX-8370.
Here are the minimum and maximum noise levels I measured during each phase of our testing:
For a stock cooler, the Wraith sounds pretty darn good. At its minimum fan speed, the cooler produces just 30 dBA, while its load noise level rises to 35 dBA on our test bench. The Hyper D92's 32-dBA idle figure is slightly worse than the Wraith's, but it doesn't have to spin its fans up when the CPU is stressed. I didn't hear a noticeable difference in the Hyper D92's fan noise at idle and under load, and that's borne out by our noise measurements.
If we throw concerns about noise to the wind, the Wraith produces about 52 dBA when set to 100% speed, while the Hyper D92 tops out at about 58 dBA. Neither of these coolers sound great if they're running all-out, but that should never happen when either of these heatsinks are cooling a stock-clocked CPU.
Decibels alone don't tell the whole story here. The Wraith's fan has a ticking character that gets worse as its speed increases. That character is only mildly evident at the speeds I chose for our testing, and I expect it'd be less audible inside a case. The ticking fades at idle, and in my test setup, the Wraith can't even be heard over the fan on my Cooler Master V550 power supply. Under optimal conditions, the Wraith lives up to its billing as one of the quieter components in a system.
I say "optimal conditions" because the Gigabyte GA-990FX-Gaming motherboard I tested the Wraith with doesn't have great fan controls. Compared to the other AMD motherboard I have in my lab, Asus' Crossblade Ranger, the 990FX-Gaming's firmware fan controls are downright archaic. By default, this board is happy to run the Wraith faster than necessary, making for a noisy system out of the box. What's worse, the board oscillates the CPU fan's speed at idle for no apparent reason, leading to a "mooing" noise from the heatsink that's both noticeable and unpleasant. Messing with the few fan settings in the board's firmware didn't change that performance much.
The 990FX-Gaming's Windows software isn't much better. The utility forgets to apply any custom fan curves set up in the software after every reboot and even after every sleep-wake cycle. Re-applying those curves isn't easy, either. Every single time I wanted to re-activate that custom curve in Gigabyte's software, I had to make a tiny adjustment to it before the "Apply" button became clickable again. That experience is worse than should be expected for a $140 motherboard paired with a $200 CPU.
None of these issues are the fault of the Wraith, but they do go to show that the CPU cooler is only one of a series of moving parts that have to come together to deliver an ideal experience. The 990FX-Gaming is one of AMD's poster children for a group of updated Socket AM3+ boards that come with modern features like M.2 slots and USB 3.1 Type-C ports, but I wish some of that initiative had gone into improving the board's fan controls and software. Similarly updated mobos from other manufacturers may perform better in the firmware fan control department, but it's hard to say without getting our hands on a few. In any case, builders should expect to spend some time in their motherboards' fan controls to get the Wraith running just right.