if you wanna update your rig :
CPU.. get an Core 2 duo proc
i;ve tested the new iDeas (1.0.2.2) n my laptop, T5500, intel C0re 2 duo 1.66Ghz with 1GB of RAM @ 667Mhz... got almost constant at 60 fps (well mostly 50-60) on dragon quest IV
if you go for core 2 duo on desktop, you'll get even more
it seem that the openGL plugin still using CPU power though (am i wrong??) coz i'm only using intel GMA 950 on my laptop, and it run quite well..