I have a quad core CPU running Centos5. When I use top, I see that running processes use 245% instead of 100%. If I use gkrellm, I just see one core being used 100%. top: PID USER PR NI VIRT RES SWAP SHR S %CPU %MEM TIME+ COMMAND 18037 thba 31 15 304m 242m 62m 44m R 245.3 4.1 148:58.72 ic Also in the log of some programs I see this strange factor: CPU Seconds = 2632 Wall Clock Seconds = 1090 There are all single threaded programs, so it's not that more cores are being used. [thba at fazant]$ uname -a Linux fazant 2.6.18-128.1.6.el5 #1 SMP Wed Apr 1 09:10:25 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux [thba at fazant]$ cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 26 model name : Intel(R) Core(TM) i7 CPU 940 @ 2.93GHz stepping : 4 cpu MHz : 1600.000 cache size : 8192 KB physical id : 0 siblings : 4 core id : 0 cpu cores : 4 apicid : 0 fpu : yes fpu_exception : yes cpuid level : 11 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpimmx fxsr sse sse2 ss ht tm syscall nx rdtscp lm constant_tsc ida nonstop_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr popcnt lahf_lm bogomips : 5871.54 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: [8] Any ideas? Thanks, Theo