Well, Mountain Lion is here. For we AMD users, three options: change to Intel, stuck with Lion i386 64-bit suporting on FX line (or Snow Leo with full functionality for all other AMDs) or hope, crossing fingers, that someone wise enough to patch a working arch x64_86 kernel pops out of the blue.

RAW, i tried the 64-bit kernel. Instant reboot, as you told me. But, remember, i have a plain Athlon II x2. No ssse. So the question is - assuming the problem affects Bulldozers as well - why does this happen? Any clue?