Video performance degrades with OC

[techm]

Hi All,

New to these forums and I recently got me E6600 and Asus P5b Deluxe MB. So I was able to easily OC the FSB to 333 and 400Mhz - the system is stable and Sandra shows increased CPU and RAM bandwidth.

Unfortunatly it seems that video performance goes down the drain. When running 3Dmark06 (also tried 05) there is noticeable drop in FPS (so obvious that I don't even have to wait for the score to know something is not right).

I tried different settings, but basicaly followed the guide specific to P5B on these forums.

So basically:

1. at stock CPU/FSB speeds everything seems to run OK. If I OC the video card (7900GS clock 600/ mem 800) I get better FPS and score in 3dmark06. So everyting seems great at this point.

2. If I OC the CPU/FSB the video starts slowing down. At this point if OC the video - things get even worse.

Here's my setup:

CPU: E6600
MB: Asus P5B Deluxe, BIOS 0614
Video: EVGA 7900GS
RAM: DDR2-800 OCZ Platinum rev1 (4-5-4-15, stable at 2.0v)

Thanks in advance!

[pablo]

what kind of power supply do you have?

[LordofDoom]

Sounds like a PSU drop. What's your power supply?
EDIT: Beat me to it pablo :)

-Satan

[[cTx]Philosophy]

Whats ur PSU?
This is definately wierd..
Download CPU-Z and check to see what ur pci-x link width is @ stock vs raising fsb/clock..

It would be a good idea to go to user cp and edit ur signature to show your exact specs in your pc so as to we could help you a little better..

LOL we all chimed inb on this one @ the same time :P

Nice work fellas..

[techm]

My PSU is ULTRA 600W
http://www.tigerdirect.com/applications/searchtools/item-details.asp?sku=ULT33133

It has 2 connectors for the videocard - one is rated at 18A the other at 20A. I think the cards is connected to one at 18A. I'll try the other.

Thank you all for the quick replies.

[techm]

you were right with FSB at 333 PCI-e width goes to x1. darn it. So this is because of the PSU?

[Bail_w]

you were right with FSB at 333 PCI-e width goes to x1. darn it. So this is because of the PSU?

you got the el-cheapo brand PSU.

[techm]

I guess you're right - I should return it and get something better. What do you recommend - you know something that won't clear the bank, but will do the job?

BTW, I used the second connector and it's now at x16 at FSB 333. I'll run some tests to see if it's stable.

[techm]

Using the second connector did the trick - I'm stable and running at 400 FSB x16.

Thank you all for the help! You guys are awesome.

[Mark099]

The same thing happens to me.

Anything over 333Mhz, and the Link Width drops to 1x. Can it be anything but a power issue?

[techm]

I'm pretty sure it wasn't the power supply. x1 on the PCI-e seems to happen with higher clocks on P5B.