Testbed and Methods

All ZEROtherm coolers we discussed today and their only competitor in this test session were tested in two modes: in an open testbed when the mainboard sits horizontally on the desk and the coolers are installed vertically, and in a closed testbed with the mainboard in vertical position

We put together the following testbed for our experiments:

• Mainboard: Gigabyte GA-X38-DQ6 mainboard on Intel X38 chipset (LGA 775, BIOS F8D)
• Processor: Intel Core 2 Extreme QX9650 (3.0GHz, 1.25V, 2x6MB L2 cache, 4x333MHz FSB, Yorkfield, C0)
• Thermal interface: Arctic Silver 5
• Graphics card: LeadTek WinFast PC8800 GTS 512MB / 256bit, 756/1877/2052MHz
• VGA cooler: Arctic Cooling Accelero S1 + Turbo Module
• Memory:
  • 2 x 1024MB DDR2 Corsair Dominator TWIN2X2048-9136C5D (1142MHz / 5-5-5-18 / 2.1V);
  • 2 x 1024MB DDR2 CSXO-XAC-1200-2GB-KIT DIABLO (1200MHz / 5-5-5-16 / 2.4V).
• Disk subsystem: Samsung HD501LJ (SATA-II, 500GB storage capacity, 7200rpm, 16MB cache, NCQ)
• Optical drive: Samsung SH-S183L SATA-II DVD RAM & DVD±R/RW & CD±RW
• System case: System case: ASUS ASCOT 6AR2-B Black&Silver (ATX) with 120mm ~900RPM Scythe Minebea fans for air intake and exhaust, and a 120mm ~840RPM Scythe Slip Stream 120 SY1225SL12L fan on a side panel
• Control and monitoring panel: Zalman ZM-MFC2
• Power supply: Enermax Galaxy EGA1000EWL 1000W (a default 135mm ~850RPM fan for intake; 80mm ~1550RPM Noctua fan for air exhaust)

Using the weakest cooling system of our today’s testing participants we managed to overclock our quad-core processor to 4GHz with the Vcore increased to 1.6V in the mainboard BIOS. The monitoring utility reported the core voltage setting a little bit lower than what was set in the mainboard BIOS: around 1.575~1.6V. The system memory was working at 1066MHz efficient frequency with 5-5-5-16_2T timings and 2.05V voltage.

All tests were performed under Windows XP Professional Edition SP2. SpeedFan 4.34 Beta 38 was used to monitor the temperature of the CPU, reading it directly from the CPU core sensor:

Its readings matched those of the Core Temp 0.96.1 utility:

The mainboard’s automatic fan speed management feature was disabled for the time of the tests in the mainboard BIOS. The CPU thermal throttling was controlled with the new RightMark CPU Clock Utility version 2.35.0 that now supports Intel Core 2 Extreme QX9650 processor.

The CPU was heated up with OCCT (OverClock Checking Tool) version 1.1.1b in a 23-minute test with maximum CPU utilization, during which the system remained idle in the first and last 4 minutes of the test:

I performed at least two cycles of tests and waited for approximately 20 minutes for the temperature inside the system case to stabilize during each test cycle. The stabilization period in an open testbed took about half the time. The maximum temperature of the hottest CPU core of the four in the two test cycles was considered the final result (if the difference was no bigger than 1°C – otherwise the test was performed at least once again). Despite the stabilization period, the result of the second test cycle was usually 0.5-1°C higher.

The ambient temperature was checked with an electronic thermometer that allows monitoring the temperature changes over the past 6 hours. During our test session room temperatures varied between 24.5 ~ 25°C. It is used as a staring point on the diagrams. Note that the fan rotation speeds as shown in the diagrams are the average readings reported by SpeedFan, and not the official claimed fan specifications.

The noise level of each cooler was measured according to our traditional method described in the previous articles with the help of an electronic noise meter – CENTER-321. The subjectively comfortable noise level was considered 34.5dBA and is marked with a dotted line in the diagram. The ambient noise from the system case without the CPU cooler didn’t exceed 33.2dBA when measured at 1m distance.

We didn’t choose the competitor for APACK ZEROtherm coolers basing on their price point. We simply decided to compare them against Thermalright Ultra-120 eXtreme super-cooler equipped with Scythe Minebea 120x120x25mm fan rotating at ~1940RPM (according to the monitoring utilities) and at ~1190RPM in its quiet mode. I believe that since the price of ZEROtherm coolers is not that much different overall, this will be more than enough to rank the coolers within the lineup and compare against one of the today’s best cooling solutions available.