@LawlessPPC

I only have 2GB. No panic log and system log offered no help.

I am also experiencing profiler saying 1 core, but everything else says 2. About this mac has wrong ram speed also. Shows 400 when I have 800.

Edit:

Update... I've gotten xbench to crash, not a kernel panic though. top details:
Process: Xbench [282]
Path: /Applications/Xbench.app/Contents/MacOS/Xbench
Identifier: com.spiny.xbench
Version: 1.3 (1.3)
Code Type: X86 (Native)
Parent Process: launchd [145]

Date/Time: 2008-07-24 16:02:10.411 -0400
OS Version: Mac OS X 10.5.4 (9E17)
Report Version: 6

Exception Type: EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000004