With 128MB of RAM, s1945p will take some time (around 10 minutes) to decrypt the graphics ROMs, but once that is done it should play fine, but it should be noted that it is rather jerky at times (fault of the emulation) rather than a constant slowdown as the arcade verson would do (although I've never actually played the arcade version).(posted 8397 days ago)Another option would be to use Kawaks which not only seems to run s1945p a bit better than MAME, but also has an option to save the decrypted graphics ROMs, so that you avoid the long loading time on 128MB of RAM. Upgrading to 256MB of RAM will certainly speed up the decryption process greatly (should only take a few seconds).