Game slows down for a second then goes back to normal.

When i move my character i notice that every now and then the screen will slightly slow then and then it will go back to normal. I did not have this problem prior to the last patch. But i also downloaded Windows 7 Ultimate while that was happening so im not sure if the OS is to blame. Its allowing me to finally play in Full Screen but if its also causing that strange slow spike then il go back to Vista.

Can anyone tell me if they are experiencing a similar issue?? Just so i have an idea if its my new OS or if its something they did during the maintenance..??

A lot of complaints about lag have been popping up since the maintenance. I doubt the OS is to blame.