Apparently the 2 cores can't all work on OS X for D620. Something with its ACPI controller I guess. Disabling one is BIOS or adding "cpus=1" flag, it works like a charm. Try it with cpus=2 flag at boot prompt, the kernel panics in a heart beat. So, live with "Core Solo", shall we?
The other thing is the SigmaTel 9200. Patched twice with HDA Patcher 1.15, one with a downloaded dump, the other with the dump generated by xubuntu, both ended up with kernel panic. Had to CPR the machine by doing "-s" at boot prompt to drop into single user mode, then /sbin/mount -uw / to enable writing, then just dump the whole /System/Library/Extensions/AppleHDA.kext/Contents and /System/Library/Extensions.cache. Reports on working 9200 on D620 are plenty, what's wrong with mine? Maybe my kernel is too old (10.4.6) for Patcher 1.15.