Wow, I thought it would be quite a while before another game that was as difficult to run as doom 3 came out. But no, you need a friggin' supercomputer for this. For me it's almost unplayable with pixel shader 1.1 at 640x480 with medium textures. It runs worse at that than doom 3 does at 800x600 and medium/low textures.
My computer is only slightly above the minimum though, 1.6 ghz duron @ 1.8, 512 mb of ram, geforce 4 ti4200. Oh well, looks like I'll have to live with 15 fps and horrible textures/resolution or wait until I can upgrade some.