very odd problem with new HD4850 512mb

Since i bought it a new Sapphire HD4850 512mb it does a weird problem.
Every now and then the sceen will go black and go back, go black and go back normal for a couple of times. It does that a lot when the video card is used in games and such.

So i called the shop and they told me it was the power supply so i changed it but the screen still flashes like that in black. So i really don't know now. Please someone help me :S

 

Is this a very brief flash or does the screen go black for several seconds?
What power supply did you buy?

 

The time it goes black varies from 1 to 5 seconds and sometimes stays black for longer. The new power supply is a Cooler eXTREME power 550W.

What i had before was a generic 550W that came with my computer when i first bought it. The guy said that new power supply was working but it's obviously not. Personnally, i think it's a faulty card but i'm not sure.

 

I think it probably is too, but Coolermaster units aren't great.

 

Nevermind, i got it replaced by a GeForce 9800gtx+ instead, not it's working and it's better.

 

Suit yourself, but you paid a lot more for a less powerful card.

 

I don't think so, the benchmark for this card is higher plus it's working fine. I couldn't get the Radeon to work at all.

 

The 3dmark is higher, as nvidia program their software to give them an artificially higher score. Overall, the HD4850 is slightly faster, but not by very much. Also, ever heard of an RMA? No company is free from faulty components.

 

No, sorry i never heard of RMA. And i'm not trying to get into a conflict with you or anything it's just that the radeon card game me too much trouble and yet it was working fine at the place i got it (even bring my comp there and it wasn't doing the problem for some reason) so i didn't have much choice. If it would've worked fine i'd be happy cuz i paid an extra 50 bucks for the geforce.

 

Exactly and you got a slower card for it. RMA basically means return the card for a replacement free of charge. You are able to do this within 30 days for anything in the US, a year or more for most things.