The system it is for is an HP xw9400. Dual Opteron 2427 Processors (12x2.22ghz) with the HP xw9400 liquid cooling system, 16gb PC2-5300 ecc ram, 4x 160gb 15k ultra 320 scsi on pci-x HP Smart Array 6400. I've two GTX 560ti 2gb and one Quadro fx 3800 in it. The power supply that comes standard with this workstation is a 1050w psu, but it only has two 6pins. The Thermaltake powerexpress is a dedicated graphics power supply that fits into 2 of the 5.25" slots. I know this system is a bit antiquated, but we just put this together for $440 off of ebay(- the 2GTXs, we had those already) and that's not a bad deal at all. Only problem is that we only have enough 6pin for one gpu. I just didn't want to fry my cards using a foreign power supply.
Thanks for the advice.