Vista 64 guest graphics driver causes display corruption

[Nephyrin]

Subject says it all:

http://www.infernalsoul.net/Junk/Dump/screenshot88.png
http://www.infernalsoul.net/Junk/Dump/screenshot87.png
http://www.infernalsoul.net/Junk/Dump/screenshot85.png

I can use the VGA driver and the machine works great. Mouse driver, etc work great, but obviously no seamless mode, or any other advantages of having the graphics guest driver.

My setup:
Virtualbox (non-ose) 2.1.4
Gentoo x64 host. Vanilla 2.6.28.7 kernel. Tried disabling tickless.
Vista x64 SP1 guest. Clean install from a RTM disk, updated to SP1, got all updates, then installed guest drivers.

I've tried:
- Fully reinstalling the guest drivers
No difference
- Using older guest drivers (212)
When i installed these and rebooted, the display worked, even resized automatically one or two times, before suddenly going completely corrupt. On subsequent reboots, it just started out corrupt (see screenshots).

Any help or ideas would be greatly appreciated
- Neph

[vbox4me2]

No idea why but I've seen this as well, reducing guest to 24bit color quality solved it, it ain't a pretty fix but it works for me