Linux Overclocking CPU stable on Windows, not on Linux

I've overclocked my CPU (4930MX) to 4.0GHz all cores with -0.45mV undervolt using IntelXTU on Windows, which saves the changes to the BIOS.
I can run Prime95 well enough on Windows without it bogging down. Sure, after about 15 minutes the CPU starts to thermal throttle (15" laptop, no miracles possible), but it rarely hits the kind of paces Prime95 puts it through on regular usage, even on Ubuntu.

I've had sensors running on Ubuntu, kept an eye on CPU usage and temperature and it all seems fine, but after a while my system just hard resets. It's obviously because of the OC. The hard reset resets the overclock setting in the BIOS and it no longer happens after coming back up with stock clocks and voltages.

Anyone else have experience with overclocking on Ubuntu and Linux in general? Were you able to work around clock issues on Linux?

 

It just means it's not a stable overclock - there are a few reasons why I might happen on ubuntu before windows. Usually it's a good idea to run several different stress testers to sort out these issues.
I've had problems before where prime95 runs perfectly over 24 hours and yet the computer would crash when playing TF2 after 20 minutes.
Back off the OC a bit and try some gaming benchmarks.