Yes, it is a BIOS issue, too many new Hackintoshes with A00 or A01 BIOS.
The other instability issue is related to Safari, I am afraid. It is now a resource hog to our 2 Gigs of memory. I went back to 10.5.6 after the last updat because of Safari 4. There is no way to remove it and go back to the older version of Safari, pre Top Sites, pre Safari 4 Beta. I had to do a fresh install. I was really hoping the new version in this update would be better, but so far it is just as buggy on my mini 9. I have to empty the cache in Safari if I am online for more than an hour or so, or whenever watching a video on Hulu or YouTube.
I don't hold out much hope for a better experience once Snow Leopard is released.
Mini 9 | OS X 10.6.7 | NBI 20100616212351| BIOS 05 | 32 GB Runcore | 2 GIGS RAM
10V | OS X 10.6.7 | NBI 20100616212351 |BIOS 06|160 GB|1 GIG RAM| 6 Cell Dell Battery
Back up Mini 9| OS X 10.6.7| NBI 20100616212351| BIOS 05 | 32 GB SuperTalent | 2 GIGS RAM