Probably not MMF2 fault, that's the video card that can't handle too well the HWA. (I'll make more tests with other accelerated games in this machine next weekend).
the system is:
Processor: AMD Sempron(tm) 2300+, MMX, 3DNow, ~1.6GHz
Memory: 256MB RAM
Display Video Card name: SiS 661FX_760_741_M661FX_M760_M741