posted: Aug. 5, 2008 @ 12:47p
Will this PSU be sufficient to power my Q6600, Asus 4850, 2 HDD, and 2 DVD drives? After reading This review I'm wondering if 4 rails are such a good idea...
Reading the rails in the comparison charts is important and this information can be found on the power supply itself and the box. While these power supplies appear to have similar rails, they are in fact quite different. The StealthXStream 600w for example claims to have four 18 amp rails which can deliver a combined output of 580 watts. However if all four rails were working at 18A the power requirement would be 216w per rail, adding up to a total of 864 watts across three rails. Obviously this 600 watt power supply is not rated or designed to handle this kind of load.
What this means is the four rails can share up to 580 watts of power, meaning if two rails are fully loaded the other two rails are limited to around 75 watts each. An even power distribution that the StealthXStream 600w could handle across all four rails would be 12A on each rail, which is 144 watts per rail. The rails are already assigned to certain devices, for example the first rail feeds power to “CPU1” while the second is shared by “CPU2” and “PCI-E2”. The third rail powers the 24-pin motherboard connector and other 12v devices, while the fourth is dedicated to PCI-E1.
On our test system the second rail could almost be maxed out under full load, as the quad-core processor and the GeForce 8800 GTX would both draw 140watts off a single rail. The fourth and first rails should only reach about 75 watt’s under load in this system, while the third rail could be maxed out by the motherboard and accessories. Therefore while the StealthXStream 600w can and did handle our test system, it is working near its limits.
That said, wouldn't I want to have the Q6600 and the 4850 each running on different rails? Why would they have their quad core cpu and the 8800 GTX both on the same rail? Something doesn't sound right.