I switched to an ATI card with maya once - never again - it was crap (and not cheap). Very slow and had major problems displaying textures but ran games like Doom and Quake 4 with no problems (thats how long it was)

Been using Nvidia now for 6 years no probs.

Any way to help with problem

Is the card dust free - if not clean it.

Is the card getting enuff power - check your rig - unplug any un-needed devices or buy bigger power supply

Do you have dual screens if so see if it works with one screen

Delete your pref (or remove them to some where else) and restart maya

Try the "power of 2 trick" fix (search it in this forum for it)

Go to display option in mayas and play with them - turning the "Baked view port texture" to fast help out my mate

Failing all that - Get a N-vidia card (or better)