I have a lot of this errors in my Centos stock 4.3 version in an Intel D945gnt motherboard with a Pentium D (dual core) If I disable apic in the grub.conf (apic=off) will I get a performance hit? Im running Asterisk on that machine. 40 is Received Illegal Vector 20 is Send Illegal Vector 60 means you're getting both errors at the same time. Basically it means that the APIC bus messages are malformed. The cause can be hardware or software, it's difficult to tell. APIC error on CPU0: 60(60) APIC error on CPU0: 60(60) APIC error on CPU0: 60(60) cat /proc/cpuinfo shows: processor : 1 vendor_id : GenuineIntel cpu family : 15 model : 4 model name : Intel(R) Pentium(R) D CPU 2.66GHz stepping : 7 cpu MHz : 2666.770 cache size : 1024 KB physical id : 0 siblings : 2 core id : 1 cpu cores : 2 fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm pni monitor ds_cpl tm2 cid cx16 xtpr bogomips : 5333.47 clflush size : 64 cache_alignment : 128 address sizes : 36 bits physical, 48 bits virtual power management: processor : 0 vendor_id : GenuineIntel cpu family : 15 model : 4 model name : Intel(R) Pentium(R) D CPU 2.66GHz stepping : 7 cpu MHz : 2666.770 cache size : 1024 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 2 fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm pni monitor ds_cpl tm2 cid cx16 xtpr bogomips : 5338.11 clflush size : 64 cache_alignment : 128 address sizes : 36 bits physical, 48 bits virtual power management: -- ------------------------------------------------------------ Erick Perez Panama Sistemas Integradores de Telefonia IP y Soluciones Para Centros de Datos Panama, Republica de Panama Cel Panama. +(507) 6694-4780 mailto: eaperezh at gmail.com mailto: eperez at ptysystems.com ------------------------------------------------------------