how to reduce my framerates?

i recently purchase a quad core ati radeon 4890 and when i use it for guild wars, it was fine, except every now and then, like 10 secs i get a freeze of 3 secs before it disappeared. for the record, my lcd can only handle up to 75 hz but my fraps ingame is around 77-78 and it keeps trying to lower down.

So i ran an antivirus in the background and another program in the background and for some weird reason my fraps drop to 60+ and the whole minor freeze thing disappeared. But i wonder if theres any other viable solution instead of opening programs in the background, hardware switching is not an option, i dont feel like going in the remove the graphics card and screws, especially with all my stuff being new and all, my graphic settings ingame are set to max level, any ideas what i can do next?

V-Sync.

Problem solved, FPS won't go over the refresh rate.

put RR in 60hz and enable V-sync or put -fps 60 in the shortcut command line

nice it works now thanks