I had the stock SH4 on a Sony Vaio with 2GB RAM and processor based graphics chip.
It worked but it ran slllooowwwww, too slow to really enjoy the game.
I recently purchased a new Dell desktop quad processor, 8 GB RAM, 64 bit, 1.2 Terabite HD and 256GB graphics card (ATI I think), which is barely enough to run the graphics properly. Software runs well but graphics card could use replacement. Also have a 22" widescreen flat panel.