8800GTX Power Analysis

After the official launch of 8800 GTX, several rumors regarding the immense power consumption of this card emerged into the wild. There was actually no need to panic but it seems PSU producers profit from every new CPU and video card launch and try to convince the buyers that they need a bigger PSU. And when I say “bigger” I don’t refer to its size.

Let’s get a few things clear here. Under no circumstances can a G80 card consume more than about 225W. A simple calculus will prove that. As you know, a video card cannot drain more than 75W from the PCI-E slot. Add a maximum of 2 6-pin power connectors rated at 75W each and you’ll get a total of 225W. And I repeat, that is actually the maximum amount of power that can be drained from the PSU, corresponding to about 19A of load on the +12 line.

225W is the maximum allowed for such a card but that doesn’t mean it consumes that much. Nvidia suggest a power consumption of 140-170W depending on the manufacturer and the cooling device since it can also drain some power. Real tests made by the guys at Anandtech revealed that a high end PC that uses an 8800GTX series card consumes about 320W. And I’m talking about a high priced Core 2 Duo with 2GBs of Ram here.

The conclusion is simple. 25-27A on the +12V lines for a single 8800 is more than enough. And in case you need a SLI configuration, make sure you have at least a 30-34A capable PSU. Note that not all PSUs run according to their specification and current on the +12V line may be lower in reality. In order to stay away from trouble, a good quality 430W-480W from a top manufacturer should be enough.