Kenka said:OK guys, I need some help to localize what my problem may be.
Recently, my monitor keep crapping on me. I linked it to my computer both with DVI and VGA cables but the problem is the same : at some point, when I play a game or a Youtube video and try to go in fullscreen mode, the screen goes black, sound stops and I get this strange "D-SUB GESTION ALIM" message (sorry, in english it means "power management")
http://i54.tinypic.com/21etelc.jpg
*snip*
Honestly, if I were you I would really chase after that video card as the first potential source. Do you have a friend or can you buy from a store locally that has a good return policy so you can test another card to see if that solves it? Or perhaps you can see if Gainward has a "cross ship" option where they send you a new card for an RMA and then you send in your old one after receipt of the new one?
EDIT: also, don't overclock or do anything that puts add'l stress on the PSU while you're troubleshooting. 550W should be enough but I am not 100% familiar with that particular model of PSU.
It's tough to diagnose over the Internet, of course...but that's what I'd do. I had a buddy with this similar problem a couple times and a new video card solved it each time (there were years in between the issues...he's not a gamer).