Undervolting with Intel' XTU - which offset should you reduce?

3

It is a pretty basic question, but I could not find an answer to this via Google.

The value you are supposed to adjust is the "voltage offset".
However, there are two kinds of values in the utility that you can both set.

  • Core Voltage Offset
  • Cache Voltage Offset

Of course, Core Voltage is what you must lower. That is no question.
But should you touch Cache Voltage Offset?
Would it lower the temperature again?

Here is an image of the said options:

http://i.stack.imgur.com/G6aA5.png

And Intel's Extreme Tuning Utility download link.

What is Intel XTU: It's a software that can be installed on Windows 7, 8, 10 and so on.
It gives you the tools to overclock, undervolt your CPU. It also includes a stress benchmark - which I did not find very useful. While it is great for overclocking, you will only meet stability issues later on if you undervolt. That's because the CPU is fine on max P-state - with the lowered voltage, but struggles to stay powered on when running at lower speeds.

Personal experience: Of course I tried it myself, set both to -70mV for example, but I could not notice a big difference, and honestly, the sensor's value is jumping all over the place when it is under load. Like it's 40-50C at idle, then it skyrockets to 70, 80, back to 50. But I see the same trend on my desktop i5/i7 as well.

Apache

Posted 2015-11-27T12:58:41.027

Reputation: 14 755

Ps.: Cannot understand why Intel cannot implement a P-state based offset. People would only need to adjust the highest P state anyway, and this would result in an increased stability overall for all undervolts. – Apache – 2015-11-27T13:02:00.600

Take really lightly what it follow, it's just a shot in darkness. About CPU power dissipation: "Both dynamic and short-circuit power consumption are dependent on the clock frequency, while the leakage current is dependent on the CPU supply voltage." So I can imagine it is to decrease the leakage that should depends from the (relative) difference of voltage: a fine tuning. Decreasing V you should always decrease T, to say how much it is all another matter...

– Hastur – 2015-11-28T15:48:15.153

Answers

0

"Generally, the cache voltage offset will normally be stable at the same level as the CPU core, while Intel HD Graphics normally hit their limit at a lower offset."

Source

avinicius

Posted 2015-11-27T12:58:41.027

Reputation: 26