I have 3x 285 GTX's, if I leave it in SLi, 2 of them run at full blast but the graphics are shoddy, probably due to lack of multicard support.
But even with just 1 going I get the same thing, running at full blast at the logon screen, although the graphics run ok in game, but in all respect, this definately isn't right.
I have a pretty good setup and not even hard graphic intensive games like Modern Warfare 2 make my cards go deep red(Imy cards have coloured LED writing down the side which go from blue[idle] to red[full load])
i7 975 EE(liquid cooled), 12GB RAM, Rampage II Extreme MB and 3x Asus Matrix 285 GTX, Windows 7 64bit,
Sounds like I'm having the same trouble. I don't know about 100% GPU activity, haven't checked that but it's safe to say this is the case, one of my case fans or the GPU fan I don't know which gets very loud. After a bit the whole system will shut down. After I restart it will do the same thing. Before now, the only time this has happened before is if I leave WoW on the character select screen too long. Running an i7 940, 6GB Ram, Nvidia GTX 295, and WIndows 7.
I was waiting for others to reply so I could chime in - I too use a single 4870 and it has no issues in the game. Though I do have my fan control set manually (my card is overclocked) and the GPU hardly ever gets above 60 at my config. I have not yet paid attention to what my GPU usage in the game is however - when they bring the game online again, I'll keep it loaded on my second monitor and let you know what I find out, in case it helps.