McAfee has always been a resource hog. I've used it on and off for about 5 years and their style of implementation has been consistent in this regard.
There is an engine patch
here that could help your resource problems.
I've also had problems uninstalling it, but that's another story.
I use Norton Antivirus (corp edition). Easier in system load, easier to update and detects viruses better in Outlook.
In my opinion of course
