Testbed and Methods
We tested Zalman CNPS9900 LED and its competitors 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 system case with the mainboard in vertical position.
Our testbed was identical for all coolers and featured the following configuration:
- Mainboard: DFI LANPARTY DK X48-T2RS (Intel X48), LGA 775, BIOS 10/03/2008
- Processor: Intel Core 2 Extreme QX9650 (3.0GHz, 1.25V, 2x6MB L2 cache, 4x333MHz FSB, Yorkfield, C0)
- Thermal interface: Gelid GC1
- Graphics card: ZOTAC GeForce GTX 260 AMP2! Edition GDDR3 896 MB / 448 bit, 648/1404/2106 MHz
- 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: Western Digital VelociRaptor (SATA-II, 300GB storage capacity, 10,000RPM, 16MB cache, NCQ)
- HDD silencer and cooler: Scythe Quiet Drive 3.5”
- Optical drive: Samsung SH-S183L SATA-II DVD RAM & DVD±R/RW & CD±RW
- System case: ASUS ASCOT 6AR2-B Black&Silver (ATX) with 120mm ~960RPM Scythe Slip Stream 120 fans for air intake and exhaust (the fans are installed on silicon spindles), and Enermax Magma fan at ~960RPM fan on the side panel. We applied noise insulation.
- Control and monitoring panel: Zalman ZM-MFC2
- Power supply: Thermaltake Toughpower 1500W W0218 (with a default 140 mm fan)
- Monitor: 24" BenQ FP241W (Wide LCD, 1920 x 1200 / 60 Hz)
All tests were performed under Windows Vista Ultimate Edition x86 SP1. SpeedFan 4.37 was used to monitor the temperature of the CPU and mainboard chipset, reading it directly from the CPU core sensor and to monitor the rotation speed of the cooler fans:
The mainboard’s automatic fan speed management feature as well as CPU power-saving technologies were disabled for the time of the tests in the mainboard BIOS. The CPU thermal throttling was controlled with the RightMark CPU Clock Utility version 2.35.0:
The CPU was heated up using Linpack 32-bit with LinX shell version 0.5.3. The RAM capacity was set at 1536MB and the test cycle included 15 runs:
Since we ran the test twice with 20/10-minute idle period between the runs for the system to cool down and temperatures to set in, the relatively short actual testing period was quite enough for the maximum processor temperature to become stable.
For the second type of load we used OCCT (OverClock Checking Tool) v2.0.1:
We ran a 23-minute test with maximum CPU utilization, during which the system remained idle in the first 1 and last 4 minutes of the test.
To conveniently control the temperatures in real time we used RivaTuner 2.21 with SpeedFan plugin. Full screenshots of our test session are given below:
I performed at least two cycles of tests in both test modes and waited for approximately 15 minutes for the temperature to stabilize during each test cycle. Despite the stabilization period, the result of the second test cycle was usually 0.5-1°C higher. We took the maximum temperature of the hottest processor core after two test cycles for the results charts.
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 temperature stayed at 23.5°C. It is used as a starting point on the temperature 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 after 1:00AM in a closed room about 20sq.m big using CENTER-321 electronic noise meter. The measurements were taken at 3cm, 1m and 3m distance from the noise source. During the acoustics tests all three 120-mm case fans were slowed down to ~700 RPM. In this mode the background noise from the system case measured at 1m distance didn’t exceed ~32.7 dBA, and the loudest fan was the 140-mm fan of the system power supply. When the system was completely powered off, our noise meter detected 30.8 dBA (the lowest on the charts is 30 dBA. The subjectively comfortable noise level is around 34~34.5 dBA.
We are going to compare Zalman CNPS9900 LED against two more cooling solutions: the previous Zalman CNPS9700 NT model (I didn’t have the non-nickel-plated LED modification available at the time of the tests), and our performance etalon – Thermalright SI-128 SE cooler ($40):
Zalman CNPS9700 NT was equipped with a PWM controlled fan that is why its fan rotation speed was adjusted automatically in the interval from 1270 to 2780 RPM. Thermalright SI-128 SE was equipped with 120 x 120 x 25 mm Enermax Magma fan ($15) that worked in two modes: at 1020 RPM and at 1580 RPM.