Trouble overclocking 4890 even slightly. PSU related?

[Dougx1317]

I recently got an ATI HIS 4890 to go with my new rig. I've read about this card being a good overclocker, but I'm having some trouble. I can run FurMark for long periods of time and the temperature never even gets to 80C. When I go to play a game like GTA 4, the computer freezes after only about 30 seconds. The screen freezes then goes black. It works perfectly on stock, but it messes up with even the slightest overclock. Does anyone have any ideas why this might be?

I'm worried that the card may be underpowered. I have an FSP 700W power supply with 4 +12v rails. I'm worried that I'm not utilizing all 700W since each rail has only 15 amps on it. Does anyone think that this could be part of the problem?

 

[Dougx1317]

Going from 850Mhz/975Mhz to 900Mhz/1000Mhz seemed to run alright for a while, but I still think it's underpowered. Is there anyway to check? Or check how many rails it is connected to?

 

[jaguarskx]

It could also be an "inferior" HD 4890 GPU that cannot be overclocked much.

FSP makes above average quality PSUs and has a good reputation. I really doubt if the PSU is the source of your problem. Just because you have a 700w doesn't mean your PC will always draw 700w of power. The PC will take what it needs as long as the PSU can dish it out.

I have no experience with the HD 4890 so you could also Google to see if there are any overclocking issues.

 

[Dougx1317]

So, is there no reason to be sucpitious of the 4 rails with only 15 amps each? Even if both PCI-e connectors are on the same rail, there is no reason to be concerned?

 

[EXT64]

I have heard that often that '4 rail' stuff is a lie. Most are really just one rail, so that should not be an issue.

 

[Dougx1317]

Alright. I'll pursue other factors that may be involved. I don't want to admit that I may just have gotten one of the "inferior" cards.

 

[EXT64]

Yeah, my 4850 wouldn't OC much at all either. I just gave up on OCing it though (it was old and had run hot for a while).