VapoChill LightSpeed [AC]
With the VapoChill LightSpeed [AC] installed into our test system, we set out to see just how powerful the unit really was, and whether or not we'd be able to overclock our particular system higher than it had ever been before. Throughout each step in the process, we recorded actual temperatures (from our CPU's thermal probe, not the LightSpeed's evaporator) and compared them to a stock heatsink and a standard VapoChill...
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Before we overclocked the test system, we tested the VapoChill LightSpeed [AC] with our Pentium 4 Extreme Edition processor running at its default clock speed of 3.4GHz. With the system idling, the VapoChill LightSpeed was able to keep our processor running at a chilly -16'C, a full 9 degrees cooler than a standard VapoChill and embarrassing the stock air cooler. We then fired up Folding @ Home and looped 3DMark03 to stress the processor and found that while under load, the LightSpeed was still able to keep the processor running well below zero.
Stock @ 3.7GHz | VapoChill @ 3.8GHz | LightSpeed @ 3.95GHz
Stock @ 3.7GHz | VapoChill @ 3.8GHz | LightSpeed @ 3.95GHz
We also performed the same tests with our system overclocked to its maximum stable speed using each of the different coolers. To achieve these speeds, we raised the CPU core voltage to 1.8v and altered the multiplier and FSB until we hit the CPU's peak. With our CPU overclocked to a speedy 3.95GHz, an increase of 550MHz, the VapoChill Lightspeed kept the processor's temperature at about -6'C at idle. When running overclocked and under load, we were finally able to stress the LightSpeed enough to bring our processor's temperature just above zero. However, with the ability to dissipate up to 240W of heat, much higher than anything we'll be able to hit with the current generation of processors, we use the term "stress" loosely. Hitting 1'C can hardly be considered "stressing" the LightSpeed.
(Note: Some motherboards report temperatures differently, depending on how their BIOS is tuned. The temperatures reported here could vary using a different motherboard.)
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;) Stock Clock Speed 3.4GHz |
;) Maximum Stable Overclock 3.95GHz |
;) SiSoft SANDRA CPU/Arithmetic Benchmark Clock Speed - 3.4GHz |
;) SiSoft SANDRA CPU/Arithmetic Benchmark Clock Speed - 3.95GHz |
Here are a few screen shots from CPU-Z and SiSoft SANDRA to show exactly how our particular CPU was configured, and how overclocking it affected performance. As you can see, performance jumped significantly in SANDRA's CPU/Arithmetic benchmark. ALU performance jumped by over 1000 Dhrystones, and FPU performance with and without iSSE optimizations jumped by 600 and 1000 Whetstones, respectively. We should also mention that this is the highest stable overclocked speed we have ever hit with this particular CPU. At 3.95GHz, the VapoChill LightSpeed was able to take our CPU about 100MHz higher than the standard VapoChill. We were even able to boot into Windows at almost 4.1GHz, but the system was nowhere near being stable.
