Strange clock problem on phenom II x6

I have a machine that shows this as vmstat -i output:

interrupt                                     total     rate
TLB shootdown                                 96203       23
cpu0 timer                                    59370       14
ioapic0 pin 19                                74663       18
ioapic0 pin 17                                    3        0
ioapic0 pin 18                                  285        0
ioapic0 pin 16                                 7905        1
Total                                        238429       59

Look at the cpu0 timer line - and imagine how this breaks everything
big time.

I tried hpet0 and ACPI-Fast as timecounter sources instead of TSC, but
this did not seem to make a difference.

Any hints what to try?

Martin

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NetBSD 5.99.65 (GENERIC) #17: Mon Feb 13 09:52:29 CET 2012
	martin <at> martins.aprisoft.de:/usr/src/sys/arch/amd64/compile/GENERIC
total memory = 16382 MB