I have an Early 2015 Macbook Pro. I removed OS X and installed Windows 10. I installed Bootcamp drivers and everything works great except for one thing.

Sometimes, not always, when playing or watching HD Youtube videos at fullscreen my computer gets really slow, so I looked at the CPU frequency and it's limited at 500MHz or 900MHz even when the CPU Usage is 100% on each core and the temperature is about 70 Degrees Celsius. This doesn't always happens, maybe I'm playing great with the CPU at 2.7GHz for hours, but sometimes event after playing 10 minutes the CPU suddenly goes down to 900MHz at best. I tried:

  • Installing ParkControl to force CPU Frequency to maximum but it doesn't work
  • Using High Performance power profile with minimum CPU State to 100%, doesn't work
  • Trying to force the CPU to get higher frequency using some CPU stress test, doesn't work

I just simply don't know what's happening, the temperature is not high so I don't think it's thermal throttling. When playing games (DotA 2 in my case) and the CPU is being limited as soon as I exit the game the core frequency goes up.

  • Your CPU is throttling itself. – Ramhound Dec 1 '15 at 18:26
  • @Ramhound Yes, but what could be the cause? – Andres Dec 1 '15 at 18:26
  • As a side note, in order to avoid high CPU usage on YouTube I suggest forcing the browser to use a hardware accelerated codec in lieu of VP9. h264ify for Chrome helps. Also, if you have a dGPU, it might be running constantly under Windows, causing the CPU to throttle. – Haider Dec 1 '15 at 18:26
  • My first guess would be heat, but 70 degrees, shouldn't be triggering it. – Ramhound Dec 1 '15 at 18:27
  • @Haider great thanks! Will try it! Ramhound yeah, and when I play for hours at 2.7GHz the temp go as high as 95 degrees without problems – Andres Dec 1 '15 at 18:28
up vote 1 down vote accepted

Ok, so the problem IS overheating apparently but with some strange behaviour. I installed ThrottleStop 8.00 Beta 5 from here and it comes with a great software called Limit Reasons.

This software monitors the CPU and gives the reasons why the CPU is being limited, in my case when I have the terrible performance problem the issue is that the signal PROCHOT is enabled when I have peak temperatures of 105 degrees which the max junction temperature. But when the temperature falls it is not disabled, the CPU keeps being limited even if I force the CPU clock multiplier the frequency won't go up. So I disabled the signal called BD PROCHOT that is almost the same as PROCHOT but it's not generated by the CPU but for external hardware that for some reason limits the CPU, for example, to protect the battery or some other component. Disabling this completely solves the problem and I don't see any dangerous temperatures in the hardware, I do limited the CPU frequency to 2.5GHz instead of 2.7GHz which makes the CPU stay about 5 degrees Celsius lower.

I hope this is useful to someone, apparently Macbook PRO are not designed to be pushed at max during long periods of time but well, that's ok, they are very slim and thermal management it's not an easy task.

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.