What does the KT333 offer over the older KT266a? Really only two things. The first one is the ability to run your memory asynchronous with your CPU bus. When your processor is running on a 133/266 bus, you can have your RAM running at 166/333 at the same time. This gives you a 25% increase in theoretical memory bandwidth. The second new feature is an improvement in the South Bridge to support ATA 133. Since most good KT266a based boards sport ATA133 RAID controllers this second feature is really no reason to upgrade.

New Soyo KT333 Dragon Ultra Review @ Neoseeker.com