Testing & Results
The CPU coolers were tested installed in a computer case in its normal orientation (a NZXT H630). A 200mm top/rear exhaust fan was added to the enclosure to aid in cooling VRMs and most of the front drive cages were removed to clear the path from the 200mm intake fan. The GPU remained installed during testing. All fans were set to 100% to remove that variable from the results (motherboard fan control was disabled). This is how I would assume most enthusiasts would set up a similar case while overclocking a similar platform.
All tests were performed using the AIDA64 Extreme Edition Stability test, using 100% fan settings on an Asus M5A99FX PRO R2.0 (PWM/motherboard fan controls were disabled for testing). The test was allowed to run until temperatures plateaued, then I recorded the ambient temperature of the intake air and began logging temperatures over the next minute. After an initial warm-up run, I ran each test at least three times (more if I received inconsistent results), and recorded the ambient temperature again. Once I had “good data,” I dropped the best and worst results and subtracted the (average over the test) ambient temperature from the median result to arrive at the delta T temperature you see in the chart.
Each time a heat-sink was swapped, the Tuniq TX-2 thermal interface material I used for each application was cleaned off of the contact surfaces with Arctic Silver’s ArctiClean two-step TIM remover, and an appropriate amount of TX-2 replaced for the next heat-sink. Due to the nature of applying TIM and mating two surfaces, I would like to adopt a 3% margin of error – even though my thermometers and the built-in thermal diode measure temperatures down to one-tenth of a degree Celsius, it could be assumed that temperatures within a degree of each other are essentially the same result.
Motherboard: Asus M5A99FX-PRO R2.0 w/ 1708 BIOS/UEFI
System Memory: 8GB (2x4GB) GSkill Ares 1600MHz DDR3 CL8
Processor: AMD FX-8320 Piledriver, 4.6GHz 1.38V/1.428V w/LLC on Extreme
Video: Sapphire Radeon 7950 3GB 1000MHz Core, 1300MHz mem
Disk Drive 1: OCZ Vertex 2 240GB
Enclosure: NZXT H630, +200mm exhaust fan (top/rear)
PSU: Rosewill Lightning 800W Modular 80+ Gold
Monitor: 1920×1080 120Hz
Operating System: Windows 7 Ultimate 64-bit w/SP1
- Motherboard Settings: LLC set to Extreme, Turbo disabled, HPC on, only CPU Mulitplier changed, 1.38V/1.428V (LLC)
There’s a couple things to keep in mind while dissecting the data in the chart above. First, the approximate load that each cooler had to dissipate was about 200W from the CPU (during the stability test, my P3 Kill-A-Watt measured around 290W at the wall, approximately 110W at idle). This is a relatively heavy load for most CPU coolers, so you won’t be able to compare these results to most Intel platforms (they would generally consume less power under load). Because of this high-heat load, you may see some coolers performing differently than they would on an alternate platform.
These are all relatively high-end coolers, ranging in price from $35 to $140. The AR01 comes in at the low end, at $34.99. While it finished at the bottom of this chart, keep in mind this cooler was designed as a quiet alternative for lower heat loads. What these results should tell you is that you should really look at spending at least $70 if you want good results with a hot CPU like an overclocked FX-8320. Still, the AR01 kept the 4.6GHz 8320 under its thermal limit, in a worst-case scenario – not a bad showing for the price.