I noticed that every time I had a microfreeze my harddrive got busy. I figure the game is accessing the harddrive to load new textures, and have to wait for the HD to deliver the info. I used a small shareware program called RAMdisk to create a dummy HD out of system memory, and installed AH2 onto it. System memory being much faster than any HD, all my microfreezes went away.
Perhaps HTC would consider preloading all the textures into system memory if the computer has memory to spare?