Hello mmowned, i have recently learned that windows vista users seem to have a latency problem on wow. And here is the fix!
First of all you have to go to X:/Windows/system32/cmd.exe
Then you have to make it a "Elevated Command Prompt". By right-clicking it and pressing "Run As Administrator".
When you have the elevated command prompt loaded up... Type in...
"netsh interface tcp set global autotuninglevel=disabled"
Without quotations. When you type it in....press enter.... then in a few seconds....it should come up under it "Ok".
Load up wow, and then you should be lag free!
Have Fun!
Ironman2173