Pentium Dual-Core E6700 runs at 1.6GHz

[idata]

Dear all,

I just replace my Pentium D 945 processor by an Intel Pentium Dual-Core E6700. At first, I really don't know the difference between Pentium D and Pentium Dual-Core. If someone wants to explain me the difference I will appreciate.

The problem I'm currently facing is the clock speed of each core. I'm running Linux RHEL on this system and when I check the processor info from /proc/cpuinfo, I saw that both cores are runnung ay 1600.00 mhz. This E6700 processor should be clocked at 3.20 GHz. The processor seems correctly detected by the OS, except for the speed. Here is a copy of my /proc/cpuinfo:

processor : 0

vendor_id : GenuineIntel

cpu family : 6

model : 23

model name : Pentium(R) Dual-Core CPU E6700 @ 3.20GHz (THIS IS OKAY)

stepping : 10

cpu MHz : 1600.000 (CORE SPEED IS 1.6GHz)

cache size : 2048 KB

physical id : 0

siblings : 2

core id : 0

cpu cores : 2

apicid : 0

fpu : yes

fpu_exception : yes

cpuid level : 13

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 constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm

bogomips : 6400.22

clflush size : 64

cache_alignment : 64

address sizes : 36 bits physical, 48 bits virtual

power management:

processor : 1

vendor_id : GenuineIntel

cpu family : 6

model : 23

model name : Pentium(R) Dual-Core CPU E6700 @ 3.20GHz

stepping : 10

cpu MHz : 1600.000

cache size : 2048 KB

physical id : 0

siblings : 2

core id : 1

cpu cores : 2

apicid : 1

fpu : yes

fpu_exception : yes

cpuid level : 13

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 constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm

bogomips : 6400.14

clflush size : 64

cache_alignment : 64

address sizes : 36 bits physical, 48 bits virtual

power management:

Is somebody can tell me why the speed of each core is the half of what it should really be?

Thank you all for you help and best regards,

Yanick Quirion

[idata · Accepted solution]

First, here is the spec sheet for a Pentium E6700 CPU:

http://ark.intel.com/Product.aspx?id=42809&processor=E6700&spec-codes=SLGUF http://ark.intel.com/Product.aspx?id=42809&processor=E6700&spec-codes=SLGUF

Yes, the standard frequency of this CPU is 3.2 GHz. But we can also see in the specs that this CPU has Enhanced Intel Speed Step (EIST) technology, in order to save power when the CPU is not being used very much, as is the case when at idle or not running a CPU intensive program. EIST automatically lowers the CPU multiplier when there is low demand on the CPU, and so the CPU frequency is lowered, usually to 1.6GHz. This is exactly what you are seeing, as EIST is no doubt enabled in your BIOS.

When the load on your CPU increases, it will switch back to it's 3.2 GHz frequency automatically. If you want to see your CPU at 3.2 GHz all the time, go into the BIOS and disable EIST. You can do this to verify everything is fine in your PC, but EIST is a nice feature to have enabled, as it saves power and allows the CPU to run cooler when not working hard.

[idata]

Hi parsec,

Thank you for your help, I was not aware of that feature.

Much thanks,

Yanick

[idata]

You're welcome, I'm not surprised the CPU speed you saw bothered you. When the information you posted was gathered, it caught your CPU at an idle period, and the EIST feature was working and we see the lowered CPU frequency.

You can monitor your CPU speed in real-time with a free utility called HWiNFO32 that is available here:

http://www.hwinfo.com/download32.html http://www.hwinfo.com/download32.html

You can watch the speed change from low to normal speed, as it will do that quite often. You'll also see other useful information about your PC. I use this myself and have never had any problem with it.

If you don't see your CPU running at 3.2 GHz at least some of the time, then another setting in your BIOS may need adjustment. If that happens, let us know in this thread and we'll try to figure that out.