7900GS Overclocking results

[Darg]

Hey, just got a 7900GS a week ago.

I did the pencil volt mod to increase the voltage to 1.4V from 1.2V default.

I could run it stable at 630/800 from the default 450/660. This is a massive overclock that let me go from 88fps on the lost coast benchmark to 102fps. I was hoping for a little better fps but I can deal with just the 15% increase.

However I just upped the voltage to 1.55V which let me take the card to 670/810 stable. The fps on the lost coast test actually dropped down to 100fps though. Can anyone help explain why that is? Should I try something around 650/800 and see if it is better then 670/810?

Kind of baffles me how the card runs slower at higher speeds. It's getting the voltages it needs to run, other people have gotten theirs to 700/860 stable on 1.55V but I'm just using the stock leadtek cooler and the ATiTool 3D furry cube causes the temps to go up to 75C. LC only raised the temps to 67 though. The card is rated safe to 130 but I'd still like to keep it 75 or lower.

 

[Defcon5]

2fps is probably within the margin of error so i wouldnt worry about that, with clocking anything you get diminishing returns after a while.

What is the volt mod btw, can you do it with pci-e cards?

 

[Darg]

I used this one:
http://endeavorquest.net:8880/7900GT_VM/index.htm

With a slightly different core volt mod. It's exactly the same PCB as the 7900GT so you can use the same volt mods.

I have my voltages now at 1.44 Core and 2.3 mem. Stable speeds are 648/900.

My only problem is that I'm hitting 73C still on leadteks stock cooler. I think when I order my mobo I'll look into getting a decent GPU cooler. Can anyone recommend one for me?

EDIT: This is the core voltage mod I used, can be done easily with a pencil. I got to 1.55V but scrubbed out some of the pencil marks to get it down to 1.44V. Note that it is quite hard to scrub out the pencil in between the pins so if you do this be careful!