Ultra ATA100 vs. Ultra ATA133 ?

[DJ-CHRIS1]

i was just browsing newegg for a new hard drive, and noticed that the Ultra ATA's are listed as either ATA100 or ATA133...what's the difference? And how do I know which one to get? My computer came with the ATA100 drive, can I put a ATA133 in it? Would the ATA133 be better?

The hard drives have a hard time saturating the ATA100 bus.

Also note that it's typically the WD and Seagate drives that are ATA100, and the Maxtor that are ATA133. WD and Seagate drives have typically been faster than Maxtor drives overall.