View Full Version : SLI clock speeds

07-05-08, 12:12 PM
I am a bit puzzled - Got my RMA back from BFG so now I have 2 GTX280 and an EVGA 750i FTW motherboard. I am powering the system with a Thermaltake Toughpower 1000W, which has 8pin and 6pin connectors on different rails for each of the graphics cards.

I have done a fresh install of Vista64 and am using nvidia driver 177.41 - I am using rivatuner to monitor clock speeds of the graphics cards.

If I run in single card mode (with either card - i swapped em around) the card runs at the full 3d clock speed in games..

If I put the system in SLI mode and start a game, the clocks jump up to the full (600Mhz+) level when the game starts.. but after about 20 sec (it is always a similar length of time) the clocks are reduced to low power 3d mode (ie 400mhz). The cards are running at 70c or so.

I tried unplugging as many powered devices as I could and it made no difference. I tried reinstalling driver/rivatuner/nforce driver - I tried using 177.39 driver. I updated to the (beta) F bios. I put my system back to standard clocks - I tried less/more voltage to northbridge. I am stuck....

anyone have an idea? :/

07-05-08, 12:23 PM
How did you know it switching? game slowdown? you running game in windowed mode?

07-05-08, 12:46 PM
I can see the clockspeeds on my G15 keyboard - and yes, the games slow down..

07-05-08, 12:58 PM
I can see the clockspeeds on my G15 keyboard - and yes, the games slow down..

What app are us using for the G15 to do this if I may ask cause I'd like to try it out? Thanks!

07-05-08, 01:04 PM

07-05-08, 01:18 PM
Force full clock speed through nvidia control panel or in worst case scenario edit bios so it's always working in full speed.

07-05-08, 01:21 PM


07-05-08, 06:24 PM
I'm not sure you can force full clock speed through control panel? I mean - clocks you set in control panel are for the full 3d - you can't set 3d low power clocks there?

and I don't really want to edit the bios on 2 rather expensive cards!

I assume it's a driver bug..

07-05-08, 06:46 PM
I found that you can force the cards to remain in "3d performance mode" with rivatuner - I will do that for now.. obviously its not ideal as my cards are now running at high speed at windows desktop but at least my games run properly now in SLI.

Hope a future driver update can fix the various problems people have with clock and fan speeds... can't believe this stuff passed QC really :/

07-05-08, 06:52 PM
Why not set up two profiles, and use the full 3d only when you game to save power

07-05-08, 07:38 PM
because I will forget to swap between them!

I will just run full speed 'til they fix the drivers.. so happy to have age of conan running at a well at last!