It will improve WoW by a few fps. Both Toms hardware and Anandtech did a review of it. My impression of the articles were the writers were trying to slam it, but there benches showed a minor improvement in most
games for the reasons harem mentioned.

it's still not worth the price IMO, but if money is no object, it does help. I put one in my main machine because I saw an improvement on the review benches, & haven't regretted it, but it will not work miracles.

No network card in existence can make what happens on the next network link from your computer happen any faster.