Normally I try to troubleshoot these kinds of things on my own, but I'm at my wits end trying to figure this out. Right now I'm using a 4930k processor on a sager NP9570 laptop. I have a tweaked bios (Prema mod) that's meant to unlock the performance of the processor that would normally be somewhat limited by the default bios (and no, I've not had any heating issues). I've had no problems with this setup whatsoever for 2 years, and now all of a sudden I have this new problem that's been driving me absolutely insane. Every now and again, the CPU clock speed gets locked down to 1.16/1.19 ghz, and it doesn't budge. Ever. It doesn't matter how demanding the task or the temperature, the core speed goes no higher. I've even used intel's processor diagnostics tool and it just flat out fails the test because the CPU refuses to go higher. The odd thing is that I can somewhat circumvent this by plugging the laptop out and in, though sometimes it takes several attempts before it properly resets. I don't know what causes the lock up, it seems to just happen at random, forcing me to plug out and plug in the charger every couple moments. At this point I don't care about having added performance, even if it just stays at no more than 3.4 ghz I'd be happy.
I've tried disabling speed step in the BIOS, however that does nothing. I used intel's XTU to disable speedstep, but then the computer just turns off a short time after logging in. It has nothing to do with heat, it will shut off even while idling at a cool 40 Celsius. The other strange thing is that, for whatever reason, each time I attempt to turn off speed step in XTU (i've tried twice), watchdog becomes "currently unavailable" for every attempt to use XTU afterward, though it can be fixed by reinstalling...
Something worth noting is that I first used XTU when I first got the laptop just to see if I could squeeze out a little bit more speed with it, though ultimately I decided to stick with default settings. The windows 8 version stayed on my computer after I updated to windows 10, and I never ran it again until recently, though when I tried I found out that version wasn't compatible with the new OS. Is it possible that, by attempting to run the outdated version of XTU, i may have caused this issue? Whenever I tried to run it, it would give me an error of some sort and wouldn't run, so I did uninstall and update to the Windows 10 version, though that didn't fix anything other than being able to use the software.
Just as a last note, I've messed with all the power settings, changing minimum processor speed to 100%, stuff like that, though nothing seems to be able to get the CPU to stop locking up. Even throttle stop can't undo/prevent the lock... Any suggestions would be really helpful. Even if the solution is kind of janky, I don't care. I'm just sick of this happening.