With the start of Cataclysm I experienced some problems while playing. Sometimes I get a freezing screen and most of the times I have fps drops/screen lag and with raiding on 25 man I don't even see effects from spells or I see them after 10 seconds (No matter what quality of videosettings I take). I first thought the problem was because maybe some drivers weren't updated and that I had to clean my pc. After I did all of this I didn't see any improvement, so I thought maybe you guys could find any solution for this problem!
Here is the setup of my computer
CPU: Intel Core 2 Quad Q6600, 2400 MHz (9 x 267)
GPU: GeForce 8800 GT (512 MB)
Memory: 3070MB RAM
Page File: 4669MB used, 1684MB available
Monitor: Iiyama 22"
OS: Windows Vista Home Premium 32-Bit
DirectX-version: DirectX 11
Already thanks in advance for helping!