Just upgraded the PC to an AMD AM2 processor on an Asus MSN motherboard, using the Nvidia chipset, and come across an interesting problem concerning the High Precision Event Timer (HPET)
Loading a Linux 2.6 Kernel gives the following error message:
Kernel Panic - not syncing: IO-APIC + timer doesn't work!
It then goes on to suggest booting with the noapic option passed to the Kernel, and sure enough, that then works.
There is another solution which is tio disable the HPET tables in the BIOS (part of the Southbridge setup routines) and with thgis disabled teh system boots normally without the noapic option.
Looking at dmesg with the HPET table and the noapic option shows that teh HPET is initialised correctly and obviously operates OK, and all IO functions seem to operate.
Similarly, looking at dmesg with HPET tables disabled and without the noapic option shows that tjhe 'normal' boot up routine operates, initialises both cores of the CPU without problem.
Googling around shows this is a problem with the Nvidia chipset which appears not to implement the HPET function correctly. (I haven't found all the tech details though)
The question is
"Which is the better option from a performance point of view? HPET and noapic, or just disable the HPET table?" My feeling is that disabling the HPET is the simplest solution, although HPET is the future direction for system timing.