Just in case someone else like me likes to try the newest Beta BIOSes, I would seriously avoid 1.75b. 1.74b is OK (apart from the continuing DPC Latency issue).
What's wrong with it? The USB controller in the SB is mis-coded. All hell breaks loose and USB ports start dropping out like crazy, if they actually work at all properly. There are some other funnies with XP too.
This affects 7519 boards- P43 Neo F and P45 Neo F