Swiftech MCW6500-T TEC (Peltier) Assisted Water Blockhardnrg - June 14, 2007
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Okay, so now I wanted to take a look at the overclocked temperatures. The highest stable overclock (24+ hours of Stress Prime 2004 Orthos Edition) on my Opteron 170 is 2817 MHz, but I run it at 2799 MHz just to be extra sure it doesn't crash - 2 MHz less HTT speed is peace of mind for me.
Anyway, I tried all sorts of voltages and settings and I could not get the CPU stable under load at the same overclocked speed (2.8 GHz) as water. I think this graph on the Swiftech site can explain what happened in this part of the testing phase.
Along the x-axis, you have increasing heat output ranging from no heat at the left, to extreme heat output for high voltage and high Thermal Design Power (TDP) processors, at the right. The y-axis shows the temperature achieved in relation to ambient temperature. So if the CPU is producing no heat at all (pretend it's a magic CPU that produces no heat at idle), then the water temperature of the Swiftech Apogee block (yellow line) is the same as ambient. Makes sense right? No heat from CPU means it's just the same as room temperature.
Okay, so the blue and red lines are the temperatures achieved with the MCW6500-T. With the magical, no-heat-output CPU, the temperature is -50°C to -60°C below ambient.
As the heat output of the processor increases, the CPU temperature compared to ambient, doesn't increase all that much with the Apogee block. The Apogee and Storm G4 perform quite similarly. The MCW6500-T however, has a steeper change in CPU temperature as the CPU heat output increases. So for high TDP processors, like the Intel Core 2 Extreme and AMD Opteron Dual Core at high voltage, there is a point where the temperature with the MCW6500-T is higher than that of the Apogee. The TEC has a limit to the amount of heat output it can handle and once that has been reached, the TEC-assisted water block becomes less effective than a regular water block. This is indicated by the background shading. So for really hot processors, you are probably just better off with water alone. I'm not talking "oh my processor is 58°C on air" hot, I'm talking "I'm surprised my computer isn't on fire" hot. I cannot run my processor overclocked on air, it runs hot at stock on air!
I was unable to run the tests fully without either the OS or an application crashing. I did manage to run the CPU only test and SP2004 Orthos Edition and MBM5 continued to run, despite other applications crashing.
The test configuration only changed by overclocking the CPU.
- AMD Opteron 170 (no heatspreader) @ 2.8 GHz, 1.632v
- Swiftech Storm G4 water-block
- Swiftech MCW6500-T TEC-assisted water-block
- Swiftech MCP655 (Laing/DD D5) pump
- Swiftech MCR220-QP radiator (2x Panaflo 120x120x38mm M1A fans @ 12v)
- Swiftech MCRes-Micro reservoir
- DFI NF4 Ultra-D (modded to SLI)
- 2x 1GB G.Skill HZ PC4000 (3-4-4-8-1T)
- 2x Point Of View 7800GT 256MB @ 522 / 1260, voltmodded to 1.712v GPU
- 2x Dangerden Maze4 GPU low profile water-blocks
- PC Power & Cooling 510 SLI/Express PSU
- Meanwell S-320-12 PSU
- 2x Hitachi 160GB 7k250 SATA1 (RAID-0)
- 2x Hitachi 250GB T7k250 SATA2
- Hitachi 200GB T7k250 ATA
- Seagate 200GB 7200.7 ATA
- NEC ND-3500A DVDRW
- Microsoft Windows XP Pro SP2
Results: Opteron 170 @ 2.8 GHz
Ambient = 26°C
This set of results compares the temperatures of each component for the system at idle on both the CPU and GPUs, against the temperatures achieved when the CPU is put under 100% load (the GPUs remain at idle)
CPU Temps (CPU Idle vs CPU Load)
PWM IC Voltage Regulator Temps (CPU Idle vs CPU Load)
GPU1 Temps (CPU Idle vs CPU Load)
GPU2 Temps (CPU Idle vs CPU Load)
The gap closes somewhat for CPU temperatures when overclocked (with the necessary added CPU voltage). The rise above ambient is +5°C for the Storm G4 and -15°C below ambient for the MCW6500-T.
During the CPU Only load test, using the Storm G4 results in a +14°C rise over ambient, but the surprise here is that the MCW6500-T can't handle the heat output of this processor at this voltage and the temperature shoots up to +23°C over ambient!
The PWM IC temperature difference is negligible. The GPU temperatures are 8 to 10°C higher using the MCW6500-T than with the Storm G4 whether the CPU is at idle or load.
The main result at this point of testing was that the Storm G4 produces a higher stable overclock than the MCW6500-T, when using a high thermal output processor that requires high voltage.