A week later, I got a hold of Corsair's high-grade 620W power supply, the CMPSU-620HX. This top-end 'enthusiast' unit is well built and, besides modular cabling for better airflow within the casing, has quite a few unique features, like solid triple +12V rails for a combined maximum output rating of 50Amp, Active Power Factor Correction (PFC), for minimal heat during operation, industrial-grade capacitors for longer lifespan, plus a double ball-bearing 120mm fan.
I thought of trying out these features, especially its voltage rail balancing at high loads, by stressing the PSU to the maximum. This time, I put that quad-core system into an actual casing, first swapping the mainboard for a simpler Asus P5N-32SLI. Since the FSB on Kentsfield doesn't overclock much, I left the ECS high-end board for Conroe's higher FSB. Connecting the same Evercool water cooling, Corsair XMS6400CL3 low-latency SLI-ready memory, and, just for kicks, added THREE GeForce 8800GTX cards. The Sparkle Calibre went in the bottom X16 slot or its Peltier Junction cooler would otherwise block the other two cards, and the two standard 8800GTX cards, one from Sparkle and the other from ECS, into the other two X16 slots. Now, what we have is a full GTX setup with two cards in SLI mode, and the third one either for another display or for, still future, physics functionality.
From the photo, you can see that the biggest problem was finding enough GPU power connectors, six in total, to feed all the cards. Keep in mind this setup is usually considered a kilowatt-class requirement, when choosing your power supply, at least according to many trade rags and high-end PSU vendors.
I expected this setup to consume at least 530W when running 3DMark06 on the SLI cards, plus a standard Windows desktop on the second display for the third card. Will Corsair's flagship PSU handle it well? Well, it did, at least for the half-day that I ran the system. It didn't even get that hot during the run, despite obviously straining itself close to the limit. However, something else did feel the heat of the moment: if you notice from the photo, there are just a few milimetres between each GeForce, affecting the cooling somewhat and that area really provided a lot of 'cosy warmth' during the benchmark run. A water-cooled GeForce with more space within the cards would, of course, solve this problem.
Again, the point is that just like 500W comfortably handled the quad-core SLI setup, so will 620W from the 620HX running the triple-card "SLI+physics Ultimate PC" setup with the same water cooled quad-core CPUs. I'm not necessarily endorsing you running it that way for say 3 years under this load, but, in the early run, the slot distances combined with thick heat GPU sinks seem to be far more of a problem. Nvidia board team, any thoughts? ?
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