sonic,
the specs for the "B" revision are not quite finalized yet that I know of (last talked to someone in the know last friday).
Here are some of the changes, and they themselves are subject to change =)
1. mount holes around cpu
2. moved AGP slot around a little...its better
3. updated voltages for vdimm and most likely others
4. SATA RAID now, no more IDE RAID
5. improved IDE/power plug location
6. heatsink on the SB chip
7. hrmm...that doesnt seem like all but ive been playing Freelancer for last 4 hours =)
As soon as the final specs are out, the site info will reflect this.
Travis