Hey Dave

I currently have an nVidia GeForce 7600 GS and run my Lacie @ 1280x1024. I dont think you would want to run any higher than this. if you need space on your desktop then i would say use a multiple monitor setup. I run CS2 on one monitor and the palettes are up on the other screen leaving me with a full screen to work with.
Was there any reason behind wanting to run at max res?
I personally dont see any problems as the monitor drivers work via the pc and not the adapter. Only thing to watch for is if the new monitor is DVI and the old one is VGA, but adapters are generally supplied with the cards/monitors anyway..
If you really want to run max res then i would say upgrade your card to a new one which runs Direct X 10 with the lastest drivers etc

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