Being a heavy player of online games, I hope this helps:

Are you using XP? if so, XP using Nvidia has a nasty bug. It defaults all resolutions to refresh at 60Hz. Pitz huh?

So, get yourself a copy of the NV refresh rate fix program from : http://www.planetquake.com/ztn/nvreffix/

This will work will all Nvidia drivers EXCEPT the latest as nvidia have changed the format of the drivers.

Hope this helps.

Fancy a duel?