In Win2k, crl-alt-del into Task Manager > Processes Tab. Click on View > Select Columns. Check boxes for CPU usage, Memory usage and Base Priority. The info in these columns can help you figure it out.
But first, decide if your prob is connection related. Does it happen when you alt-tab out of AH OFFLINE play? If it does, you rule out a connection issue.
I didn't have a connection issue, so I re-installed the latest 4-in-1's, reinstalled my video drivers using Det Destroyer in between, and reinstalled DirectX 8.1. No change. I removed custom sounds from AH, and tried running with original sounds. No change. I removed and replaced AH entirely. No change. ( By the way, if you have more than one tweak program, I recommend getting rid of all but one, and just use that one to reduce the chance of problems between them.)
Finally, I looked closely at the Processes tab in Windows Task Manager. I decided to close out the processes using the highest amount of memory after AH, and test in between. The very first one, using about 8,000k, was the culprit.
It turned out to be a realtime antivirus checker that was running without me knowing it. I disabled it, and AH went from using 58-61,000k minimized, to 29-34,000k when minimized. Problem solved.
Hope you find a clue to your problem here, Ammo... G'luck