Weird problem with WoW

Sorry if this isn't in the right category, but I'm not really sure what exactly the problem is so I put it here. Basically I get large lag spikes when playing World of Warcraft and the general latency is rather high. I also tried port forwarding which didn't help. Before I get more in depth with the issue I need to say that my computer is running wifi through linksys router, and I also need to state that I was experiencing lag through other games that was attributed to Vista looking for wifi networks. I installed a program to disable that and now all my games except Wow run perfectly. The computer I ran all that on was with 64 bit Vista.

Now here's where the problem gets a little more complex. I run WoW perfectly on my other computer which is a 32 bit windows xp machine. It runs on the same router and networking card. So basically I'm thinking this has to be a vista issue, or possibly a WoW issue or maybe both. For now I have ruled out any type of networking issues, but I'm also not too tech savvy so if anyone has any idea I'd be willing to try them.