Testbed and Methods

All tests were performed inside a closed system case. Our testbed was identical for all coolers throughout the test session and featured the following configuration:

• Mainboard: ASUS P6T Deluxe (Intel X58 Express), LGA 1366, BIOS 1504;
• Processor: Intel Core i7-920, 2.67 GHz, 1.25V, 4 x 256 KB L2, 8MB L3 (Bloomfield, C0);
• Thermal interface: Arctic Silver 5;
• Graphics card: ZOTAC GeForce GTX 260 AMP2! Edition 896 MB, 648/1404/2108 MHz (1030 RPM);
• Memory: DDR3 PC3-12800 3 x 2 GB OCZ Platinum Low-Voltage Triple Channel (Spec: 1600MHz / 7-7-7-24 / 1.65 V);
• Disk subsystem: Western Digital VelociRaptor (SATA-II, 300 GB storage capacity, 10,000 RPM, 16 MB cache, NCQ);
• HDD silencer and cooler: Scythe Quiet Drive 3.5”;
• Optical drive: Samsung SH-S183L;
• System case: Antec Twelve Hundred (default 120 mm fans replaced with Scythe Slip Stream 120 fans at 840 RPM; 120 mm Scythe Gentle Typhoon at 840 RPM installed on the lower front of the case; standard 200 mm fan at 400 RPM at the top of the case);
• Control and monitoring panel: Zalman ZM-MFC2;
• Power supply: Thermaltake Toughpower XT 850 W (with a default 140 mm fan).

During this test session we managed to overclock our 45nm quad-core processor with the multiplier set at 21 and “Load-Line Calibration” enabled to 3.99 GHz (+49.6%) using the weakest cooling system of the today’s testing participants. The nominal processor Vcore was increased to 1.36875 V in the mainboard BIOS.

The memory voltage was at 1.64V and its frequency was around 1520MHz (7-7-7-14_1T timings). All other parameters available in the mainboard BIOS and connected with CPU or memory overclocking remained unchanged (set to Auto).

All tests were performed under Windows Vista Ultimate Edition x86 SP1. We used the following software during our test session:

• Real Temp 3.20 RC4 – to monitor the processor core temperature;
• Linpack 32-bit with LinX shell version 0.5.9 – to create maximum CPU load (two test cycles, 15 Linpack runs in each cycle with 1624 MB RAM capacity involved);
• RivaTuner 2.24 – to visually control temperature changes (with RTCore plugin).

So, the complete screenshot during the test session looks as follows:

The stabilization period for the CPU temperature between the two test cycles was about 10 minutes. We took the maximum temperature of the hottest processor core of the four for the results charts. The ambient temperature was checked next to the system case with an electronic thermometer with 0.1 °C precision that allows monitoring the temperature changes over the past 6 hours. During our test session room temperature stayed at 23.5-24 °C.

The noise level of each cooler was measured after 1:00 AM in a closed room about 20 m² big using CENTER-321 electronic noise meter. The measurements were taken at 1 m and 3 m distance from the closed system case. During the acoustics tests all five 120 mm case fans were slowed down to ~520 RPM. In this mode the background noise from the system case measured at 1 m distance didn’t exceed ~33.3 dBA. When the system was completely powered off, our noise meter detected 28.8 dBA (the lowest on the charts is 30 dBA). The subjectively comfortable noise level is around 34.5~35 dBA.

Keeping in mind the design of the Alpenfoehn Brocken cooler, we picked a tower-cooler of similar structure and highest cooling efficiency – ThermoLab BARAM ($50). We tested this cooler with one and two 120 mm Scythe Slip Stream 120 fans ($9.70) at ~830 and ~1880 RPM rotation speeds. We also tested our today’s hero, Alpenfoehn Brocken cooler, with the same fans (marked as “SS” on the diagrams):

Our ultimate performance reference, Thermalrigth IFX-14 ($79.90), which is the today’s best CPU air-cooler, was also included into this test session with one and two identical fans installed:

Well, let’s check out the results now!