Overclocking 7950GT's in SLI with 2 x Zalman FC-ZV9 Dual Heatpipe Coolers + Photo's

[chinobino]

Well I have been running 2 x 7950GT's via SLI for a couple of months now and have been enjoying much higher resolutions in games. Although my XFX cards are pre-overclocked I decided to push them even more for some serious SLI performance... I discovered that the GPU's can do 660MHz stable up from the default 570MHz. I increased the GPU voltage from 1.25V to 1.35V permanently by modding the BIOS. That's higher than two 7900GTX's and with less voltage (1.4V).

This of course resulted in a lot more heat being produced - the cards were only 47°C when idle but hit 90°C on load . I realised I needed better cooling. I needed active cooling. I decided on a dual heatpipe + fan combination - enter the Zalman's!

Here are some photo's of the XFX cards before modding.





Factory heatsink off.



Two naked cards cleaned up.



RAM sinks attached.



Heatpipes/Fans attached.



Testing the fans.



Oooh perty!



The resulting reduction in temperature is amazing;

Idle temp ~37°C (down from 47°C)

Full load ~61°C (down from 90°C)

Much better!

I may even do another volt mod to see if I can go higher on the GPU... now where's my conductive ink?

[Tweakurr]

Nice work Chino! Now I am about to enter the SLI world myself as I have another 7900 on the way in 3 days time. Does it work in Vista 32 anyone?

[Tweakurr]

Ok, got SLI working after flashing both card bios's to GTO. Now running 520/ 720 (default was 450/660). You mentioned adding voltage thru the card bios, how did you do that?

BTW: SLI does work in Vista32