Don't forget this setting guys...
Irish, go into your sh4 folder > \data\cfg Look for a "main.cfg", open with notepad, make sure you don't set it to always use notepad to open the file, that is, uncheck that little box.
After you open the file, look for this section near the end...
[DEVELOPING]
DevDebugEnable=Yes
DevEditEnable=Yes
MiniDump=Yes
Change the "yes" to "no" and save. Those default settings were killing my framerates.
In your video card properties, make sure you turn off "fast writes", those are a no no for Ati cards.
Also try setting your video settings for direct 3d to "application preference". Mainly to start out and see if the framerate improves. If it's better, then start bumping things up.
Hope that helps, I was playing with 1 gig of ram and the game was still playable, but I do have a little newer video card. Good luck
Btw, I'm not knocking anyones recommendations for more ram, more would be better, but I'm hoping Irish will be able to at least play until then.
A good bunch of guys here. Helped me with a few issues.