I used to play games on that laptop over WiFi and I've never noticed any problems.
I don't have any problems while playing games, either. I played a bunch of TF2/CS:S and it was fine. And most web surfing is fine. It's only when it's downloading a huge single file from the web, or copying huge single files across the local network.
It was my main PC for nearly a year and I never noticed anything when downloading or uploading large files *shrug*