I'm getting a lot of these messages showing up in dmesg output. What is a lot? At this point, 314 during my 3 days of uptime. Description of system: - HP Pavilion a1350n desktop computer - AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ - ATI chipset - nVidia 7800GTX PCIe video card (and 450w Antec power supply to support it) - Fedora Core 4 for x86_64 with updates as of last week - kernel-smp-2.6.15-1.1831_FC4 for x86_64 >From http://lkml.org/lkml/2004/4/5/280 I infer that this message means "Receive Illegal Vector" on the APIC bus. I would guess that booting with "noapic" would suppress the problem. I would rather solve it. My machine is new and under warranty (but HP does not support Linux). => if you are running a Athlon X2 CPU, could you check to see whether you are getting these messages too? dmesg | grep 'APIC error' I'd be interested in hearing from you either way. Please describe your system. => The machine came with WinXP MCE. Is there any way I should be able to observe this problem from WinXP? That would make it easier to ask for support from HP. Anecdote: I used to get APIC errors, years ago, on my Abit BP-6 motherboard running dual Celeron 300A CPUs. I just put it down to the fact that: - Celerons were not specifieded to be dual processors (but lots of folks did run them this way) - Celerons were on speced to run 50% overclocked (but this was considered to be Standard Operating Procedure by most folks) - the BP6 signal runs were not designed as Intel specified for a dual processor