Im a currently working on a way to reduce power consumption and related heat dissipation. A good way on Core 2 CPUs was to play with Fid and Vid.
On linux, I load the msr module from the kernel : modprobe msr
And then I can affect Vid and Fid. On my Core 2 E8500, I was able to reduce power consuption by 15% without an impact on performances, by undervolting cpu for max frequency using for example :
wrmsr -p 0 0x199 0x0223
And applying this value every 0.1s.
I am looking for a way to do the same on Nehalem/Westmer, Sandy Bridge/IvyBridge, and Haswell. However, I do not find any documentation to know if it's still possible on the Intel Xeon series (I am using an E5520 for testing), and what are the msr addresses to be used to know defaults Fid/Vid and to change on the fly currently used Fid/Vid.
Is there a specific PDF or web page that regroups these informations ?
With My best regards.