We asked Puget what its goals were in building this thing and, perhaps more important, what was their customer hoping to get out of it. They answered with the following:
"Our client came to us with a need we hear often: he wanted a high performance machine, but wanted it quiet. Of course, “quiet” is a subjective term... Building a mainstream PC to be quiet isn't difficult at all, but high-performance machines are more challenging. This particular computer has four quad-core Opteron processors, 32 GB of memory, two VelociRaptor hard drives in RAID1, and six 1 TB hard drives in RAID 5. That's not a easy machine to make quiet! We opted to cool the machine with a massive radiator mounted to the side of the case, providing an extreme amount of radiator surface area, allowing us to run the fans at 5 V for nearly silent operation. And the temperature on the CPUs? 36 C at idle, 45 C at load.
We begin by testing the board under air cooling, to make sure the motherboard, CPUs, and memory are working properly. It takes half a day to run one pass of MemTest!"