We are adopting the following methodology on our CPU cooler reviews.

First we chose the CPU with the highest TDP (Thermal Design Power) we could: a Core 2 Extreme QX6850, which has a 130 W TDP. The choice for a CPU with a high TDP is obvious: as we want to measure how efficient the tested cooler is, we need a processor that gets very hot. This CPU works by default at 3.0 GHz, but we overclocked it to 3.33 GHz, in order to heat it as much as possible.

We took noise and temperature measurements with the CPU idle and under full load. In order to achieve 100% CPU load on the four processing cores we ran Prime95 on the "In-place Large FFTs" option and three instances of StressCPU program, at the same time.

We also compared the reviewed cooler to the Intel stock cooler (with copper base), which comes with the processor we used, and also with some other coolers we tested using the same methodology.

Temperature measurements were taken with a digital thermometer, with the sensor touching the base of the cooler, and also with the core temperature reading (given by the CPU thermal sensor) from the program SpeedFan. For this measurement we used an arithmetic average of the four core temperature readings.

Sound pressure level (SPL) was measured with a digital noise meter, with its sensor placed 4" (10 cm) from the fan. We turned off the video board cooler so it wouldn't interfere with the results, but this measurement is only for comparative purposes, because a precise SPL measurement needs to be done inside an acoustically insulated room with no other noise sources, that we do not have.

Hardware Configuration

• Processor: Core 2 Extreme QX6850
• Motherboard: Gigabyte EP45-UD3L
• Memory: 2 GB Corsair XMS2 DHX TWIN2X2048-6400C4DHX G (DDR2-800/PC2-6400 with timings 4-4-4-12), running at 800 MHz
• Hard drive: 500 GB Seagate Barracuda 7200.11 (ST3500320AS, SATA-300, 7200 rpm, 32 MB buffer)
• Video card: PNY Verto Geforce 9600 GT
• Video resolution: 1680x1050
• Video monitor: Samsung Syncmaster 2232BW Plus
• Power supply: Seventeam ST-550P-AM
• Case: 3RSystem K100
  

Software Configuration

• Windows XP Professional installed on FAT32 partition
• Service Pack 3
• Intel Inf driver version: 8.3.1.1009
• nVidia video driver version: 182.08

Used Software

• Prime95
• StressCPU
• SpeedFan

Error Margin

We adopted a 2 ^oC error margin, i.e. temperature differences below 2 ^oC are considered not relevant.