Under-volting for the first time and i'm confused (short, I promise)

Discussion in 'Mobile Computing' started by zamardii12, May 19, 2018.

  1. zamardii12

    zamardii12 2[H]4U

    Jun 6, 2014
    Hey everyone. I'll keep this short and sweet. Got a new laptop with a i7-8750H and i'm under-volting for the first time. I am using Intel's XTU and i'm currently at -0.100 on my Core Voltage Offset and it's stable at idle and on load (no crashes). However, I am noticing now since under-volting that during stress tests the "Power Limit Throttling" turns yellow and changes to Yes at a regular interval. What does that mean? I read online it means that I should increase the Turbo Boost Power Max wattage since apparently the CPU is not getting to full boost speed with the current undervolt. Is that true? I am afraid to up the wattage anymore since the default was 45 and i'm at 60 now and I have no idea where the ceiling is. The whole point here is to get more battery life and performance out of this, but I don't want to mess up my new laptop either.

    When stress testing the max core frequency stays at 3.88GHz most of the time, but when Power Limit Throttling turns on it jumps down to 3.72GHz and back again to 3.86GHZ and back down to 3.72GHz.

    Now I am running Prime95 and Max Core Frequency is 3.38 and Power Limit Throttling is always on. I also put the Turbo Boost Power Max back down to the default 45 watts. Before I started any of this undervolting, I was getting sustained Max Core Frequencies of 4.00GHz and now after undervolting I am only getting 3.37. But again, I think that's because the Power Limit Throttling is always on. I did notice however that sustained Package Temperature is a low lower than before.

    After 8 minutes of testing the Max Core Frequency is down to 3.02.

    I thought the point of undervolting was to decrease power needs but retaining full CPU power. What am I doing wrong?

    *Update: After returning all settings to what I think were the defaults, I am getting "Power Limit Throttling" during Prime95. Is that normal?
    Last edited: May 19, 2018