Cpu frequency at 1600 mhz instead of 2400 mhz

cabron · 09-21-2007, 08:33 AM

I have a Core 2 Duo 6600 at 2.4 ghz.When i looked in my cpanel it showed me either 1600 mhz or 2400 mhz.

Like this:

Quote:

Processor Information

Processor #1 Vendor: GenuineIntel
Processor #1 Name: Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz
Processor #1 speed: 1600.000 MHz
Processor #1 cache size: 4096 KB

Processor #2 Vendor: GenuineIntel
Processor #2 Name: Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz
Processor #2 speed: 2400.000 MHz
Processor #2 cache size: 4096 KB

Quote:

Processor Information

Processor #1 Vendor: GenuineIntel
Processor #1 Name: Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz
Processor #1 speed: 2400.000 MHz
Processor #1 cache size: 4096 KB

Processor #2 Vendor: GenuineIntel
Processor #2 Name: Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz
Processor #2 speed: 1600.000 MHz
Processor #2 cache size: 4096 KB

Or both 1600 or 2400....

Also:

Quote:

root@host [~]# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz
stepping : 6
cpu MHz : 1600.000
cache size : 4096 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 2
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
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 pbe nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm
bogomips : 4790.75
clflush size : 64

processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz
stepping : 6
cpu MHz : 1600.000
cache size : 4096 KB
physical id : 0
siblings : 2
core id : 1
cpu cores : 2
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
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 pbe nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm
bogomips : 4787.99
clflush size : 64

Now what's the problem with it?

I run fedora 5 2.6.20-1.2316.fc5smp.

Is it a hardware issue or an os issue?

macemoneta · 09-21-2007, 08:51 AM

It's not an issue, it's a feature. The CPU is throttling (reducing power consumption) when idle. The information you are looking at is just reporting the current state.

crashmeister · 09-21-2007, 08:57 AM

Could also be the mobo - mine reads 1950 Mhz while the CPU is running 2950 Mhz.

macemoneta · 09-21-2007, 09:07 AM

Easy way to check... Open two terminal windows (one for each CPU) and in each run:

Code:

while true; do true ; done

You can stop the above with a ctrl-c. It's a CPU loop; run it for a few seconds and then check /proc/cpuinfo (in a third window). If the CPU MHz reports 2400, then the throttling is working. When you ctrl-c the MHz should return to the lowest power value (assuming the machine is otherwise idle).

cabron · 09-21-2007, 09:08 AM

Quote:

Originally Posted by macemoneta

It's not an issue, it's a feature. The CPU is throttling (reducing power consumption) when idle. The information you are looking at is just reporting the current state.

Will this affect performance?

macemoneta · 09-21-2007, 09:32 AM

No, performance is not impacted. As soon as there is a demand on the CPU (as exemplified by the loop test in post #4), the CPU returns to full performance. Depending on the CPU, it may have multiple power saving states. In that case, the CPU will throttle-up just enough to meet demand.