Since I have a 400mhz pc. I use mame37b16 which is the fastest. Some of your new roms will work but some won't. The easiest to get roms is by searching google for gp2x mame roms, since the mame version used in that version is mame 0.34 with some extra games addded from the 0.3xx versions.
Some CHD games won't run even with the newest hardware.