We are a McAffe shop too... thousand's of users on it. Talk about bringing a Pentium 4 to it's knees. Thankfully I got upgraded to a new Pentium Dual Core workstation and my loathing of McAffe has subsided, but's it's crazy how much of a CPU that thing sucks down.
I traced McAffe's problem for us to when Windows Updates checks for updates, it has a catalog of .cab files in a cache folder, when Windows Updates reads those files, McAffe trips out and pegs out it's CPU for a couple of minutes. If you try to do a simple copy and paste of those .cab files, it will do the same thing and take hours to copy them.
Yeah I wonder who's bright idea was it to make that transparent firewall prompt covering the entire bottom half of the screen when it detects software wanting to go out on the internet. They put that transparency thing in an update about a half a year ago and it almost killed all of our older laptops.
I guess the only good thing about this was I was able to use this as an example why we needed to buy new laptops for some of the employees who were using Celerons and P4's. lol