Replaced Matrox Parhelia with NVidia

My Matrox Parhelia 128 had been a reasonable 2D card under Windows but was becoming more of a struggle to keep going under Linux. Matrox’s little supported Linux drivers did not support the key feature of the card that I wanted – hardware zoom – and I couldn’t get Compiz Fusion (which has a nice software zoom) to work with it.

I bought an NVidia 7600GT to replace it; hardly the latest graphics powerhouse but I thought it would be more than good enough for running the Compiz desktop under Linux and maybe even the odd game.

The NVidia XP drivers support hardware zoom under Windows, so that feature was covered. Under Linux I eventually got Compiz going and its software zoom and other shiny graphical features are nice.

Hardware wise, the first thing I noticed was that the big bright fan heatsink was amazingly close to my GL824 card in the adjacent slot. I wedged a small plastic separator between the cards to make sure they dont bump.

Second thing I noticed is that the heatsink gets hot even if I’m not running the 3D desktop or doing anything graphic intensive. On a warm day it sat around 76 degrees. I got it down to 72 by underclocking the card (see below). I’ve then bumped up the rear case fan speed (making the machine more noisy), the temperature sits in the 60s now.

Guess I was too used to the power (and performance) miserly Matrox.

One thing that has me stumped; when X isn’t running, the card goes crazy heat wise, it gets to about 85C! What is it doing when X isn’t running? Is this a bug? I’ll have to try it under Windows when its sitting at a full screen CMD window to see.

Over/Under Clocking The 7600GT Under Linux

I found out how to enable clock adjustment in the card. In my xorg.conf I have:

Section “Device”
Identifier “Videocard0”
Driver “nvidia”
Option “AddARGBGLXVisuals” “True”
Option “Coolbits” “1”

Then I’ve set this up to execute when my X session starts:

nvidia-settings -a GPUOverclockingState=1
nvidia-settings -a GPU2DClockFreqs=150,200
nvidia-settings -a GPU3DClockFreqs=150,200

This change brings the temperature down about 4 degrees. I must say I am a bit disappointed that so much heat (and power) is being wasted by the card when I’m not using the 3D capabilities. The world of graphics GPUs that use more power than the main CPU is very new and strange to me.