Testbed and Methods

All today’s testing participants 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.

Our testbed was identical for all coolers and featured the following configuration:

• Mainboard: ASUSTek P5K Deluxe/WiFi-AP (Intel P35), LGA 775, BIOS 0809
• Processor: Intel Core 2 Extreme QX9650 (3.0GHz, 1.25V, 2x6MB L2 cache, 4x333MHz FSB, Yorkfield, C0)
• Thermal interface: Arctic Silver 5
• Graphics card: Sparkle GeForce 8600 GT 256MB / 128bit (passive cooling)
• 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 3.85GHz with the Vcore increased to 1.525V in the mainboard BIOS. The monitoring utilities reported the core voltage setting a little bit lower than what was set in the mainboard BIOS: around 1.5V. When we tested our CPU for maximum overclocking with each cooler, we increased the CPU clock frequency and voltage accordingly.

All tests were performed under Windows XP Professional Edition SP2. SpeedFan 4.34 Beta 44 was used to monitor the temperature of the CPU, reading it directly from the CPU core sensor:

The mainboard’s automatic fan speed management feature was disabled for the time of the tests in the mainboard BIOS (except for coolers with PWM support). The CPU thermal throttling was controlled with the new RightMark CPU Clock Utility version 2.35.0:

The CPU was heated up with OCCT (OverClock Checking Tool) version 2.0.0 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 next to the system case 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 32.5dBA when measured at 1m distance.

We decided to compare the performance of our today’s testing participants against that of ZEROtherm NV120 Premium cooler, which is priced similar to ASUS solutions. We tested this cooler only in one operational ode: at ~1,490RPM fan rotation speed and moderate noise level.