You don't need to. UDMA133 is a marketing gimmick from Maxtor and has no influence on performance. Get a good quality drive and do not be concerned about UDMA100 vs. UDMA133. I recommend the special edition Western Digital drives. Further, they come with a 3 year warranty.
<i><b>Engineering is the fine art of making what you want from things you can get</b></i>
<A HREF="http://www.btvillarin.com/phpBB/viewtopic.php?t=655" target="_new">My systems</A>