mhz is our piece of code which displays  the actual frequency of the Core i7

• download and compile the source code

$ gcc mhz.c -o mhz

• change for root the owner of the executable, then change its attributs with a setuid.

# chown root mhz
# chmod u+s mhz

• make sure to load before, the following Linux daemons which provide access to the MSR registers and the SMBIOS structures

# modprobe msr
# modprobe dmi-sysfs

• then run the program with core number as the only argument.

$ mhz 3
3200

We are releasing a coremod source code snapshot.
This nightly build version provides :

• the reading of the processor features, based on the CPUID instruction
• the performance of the Core i7 frequencies, using the MSR registers
• the DDR3 latency timings through the I/O of the memory controller

Building CoreMod from source files is explained into the Wiki

The last release is 2012-0.1.2

By the way, we have added a lastest function to display the system summary.

The coremod programming is on its way with new functions to display and dump the followings :

• the clock frequencies and the temperature for each core,
• the processor features,
• the cache memories,
• the bios
• the motherboard

Stay tuned for source code …

Right after our previous post about overclocking the Intel Core i7 processor, we are providing here a software way to read two of its main settings :

1. The external clock, named Base Clock [BCLK] in the BIOS
2. The clock ratio of each logical core [Ratio]

• reminder : the CPU frequency being the product of the Ratio and the Base Clock.

At our disposal, two substantial guides :

1. The Intel 64 and IA-32 Architectures Software Developer’s Manual Volume 3
2. The SMBIOS Reference Specification © Distributed Management Task Force

Both volumes doing a two thousand pages sum , let us suggest you in the wiki a software framework called ″coremod″ which will be completed as soon as we would have a better understanding of the system design.

Requirements :

1. The Linux Operating System
2. Running as root
3. Loading these two kernel modules  : msr and dmi-sysfs
4. A C compiler ( gcc or clang will be just fine )
5. An optionnal debugger such as DDD

Notices :

¹ ″coremod″ starts with none one or two arguments, respectively the first and last core to read.

² No arguments checking is done. You must know your processor specification and its number of logical cores.

³ CyrIng denies any responsability of the execution consequences of the freely given opened source.

Illustration of the coremod debugging

Execution output

Intel has lauched the “Performance Tuning Protection Plan” to replace some processors dead after overclocking !

Below, the estimated price at the present day

A few bits of code to read the Base Clock frequency of the Rampage II GENE BIOS.

$ clang bclk.c -o bclk
# ./bclk

BCLK=160 MHz