Testbed and Methods
The coolers were tested on an open testbed and in a closed system case with the following configuration:
- Mainboard: ASUS P5K Deluxe/WiFi-AP (Intel P35 chipset, LGA775, BIOS 0601)
- Processor: Intel Core 2 Quad Q6600 (2400MHz, 1.2875V, 266x4MHz FSB, 2x4096KB L2 cache, Kentsfield B3)
- Thermal interface: Arctic Silver 5
- Graphics card: Sysconn GeForce 7900 GS GDDR3 (256MB, 256-bit bus, 575/1710MHz)
- Graphics card cooler: Arctic Cooling Accelero S1 in passive mode
- Memory: 2 x 1024MB Corsair Dominator TWIN2X2048-9136C5D DDR2 SDRAM (SPD: 1142MHz, 5-5-5-18, 2.1V)
- Disk subsystem: Samsung HD501LJ (SATA-II, 500GB storage capacity, 7200rpm, 16MB cache, NCQ)
- Optical drive: Samsung SH-S183L DVD-burner (SATA-II)
- System case: ASUS ASCOT 6AR2-B Black&Silver with two 120mm 980rpm system fans Sharkoon Luminous Blue LED for intake and exhaust and a 120mm 940rpm GlacialTech fan on a side panel
- Power supply: Enermax Galaxy EGA1000EWL 1000W (a 135mm 850rpm fan for intake and a 80mm 1650rpm fan for exhaust)
The quad-core CPU with a polished heat-spreader was overclocked to the maximum stable frequency it had with the weakest cooler. That was 3159MHz. The core voltage was set at 1.3875V.
CPU-Z, SpeedFan and Everest reported a core voltage of 1.364V. The memory voltage was increased to 2.1V. The other mainboard voltages were left at their defaults. I set the CPU Voltage Reference at 0.63x and the CPU Voltage Damper at Enabled in the mainboard’s BIOS Setup.
All tests are performed in Windows XP Professional Edition Service Pack 2. SpeedFan 4.33 is used to monitor the temperature of the CPU, reading it from the CPU sensor.
The CPU is heated up by means of OverClock Checking Tool version 1.1.1b in a 24-minute test during which the system remains idle in the first and last 4 minutes for the temperature to stabilize.
The mainboard’s automatic fan speed management (Q-Fan technology) is disabled for the time of the tests. The thermal throttling of the Intel Core 2 Quad processor is controlled with RightMark CPU Clock Utility version 2.30. Our CPU begins to skip clock cycles on reaching a temperature of 82°C and higher.
I perform at least two cycles of tests and wait for 20 minutes for the temperature to stabilize during each test cycle. The maximum temperature of the hottest CPU core in the two test cycles is considered as the final result (if the difference is not bigger than 1°C – otherwise the test is performed once again). Despite the stabilization period, the result of the second cycle is usually 0.5-1°C higher.
The noise level of each cooler was measured according to our traditional method. The subjectively comfortable level of 36dBA is marked with a dash line in the diagram; the ambient noise from the system case, without the CPU cooler, was about 34dBA when measured from a distance of 1 meter.
The ambient temperature was monitored by means of an electric thermometer and remained at 22.5-23°C during the tests (marked with a red line in the diagrams). The fan rotation speeds are shown in the diagrams as reported by SpeedFan. ASUS’ P5K mainboard series does not support PWM-based regulation of the CPU fan, so I set the subjectively quiet mode for the OCZ coolers manually with SpeedFan.
One of the opponents to the new coolers has been mentioned in the specifications table. It is the Cooler Master Hyper TX 2, the universal version of the Hyper TX we had reviewed earlier. This cooler was tested in two modes: quiet (at 1510rpm) and max speed (1900rpm, which is not actually loud, either). I also added the Thermalright Ultra-120 eXtreme as a performance reference f(and other characteristics) among air coolers. It was tested with a 120x120x32mm fan from SilverStone (the FM122 model) in two modes: quiet (at 1130rpm) and loud (2550rpm).