The first time I tried Quake III Arena on my Dell last month, it was creepy slow. Now they've added hardware acceleration, so there is reason to believe it's more smoothly now. Unfortunately according to the developers, X51v users might not have sufficient RAM to start the game.

Find me at Aximsite or Mobileread

how much ram do they expect users to have? a lot of other pda's don't have more than 64MB

There is more information on what it supports and on how to get it running here:
http://www.aximsite.com/boards/showthread.php?t=100238