I've a MacBook Pro 15" late 2013. For a long time I have encoded videos with handbrake and the CPU was very hot for hours. The clock speed was about 2.8GHz (I have the 2.3GHz model) and the temperature was over 95°C. In one of the last updates of High Sierra I think there was some modification such that now the CPU speed while encoding a video is about 1.8GHz and the temperature is always lower than 80°C. What can I do? I've lost about the 35% of the power of my mac….
CPU speed of the Macbook Pro Retina downclocked
cpuperformancetemperaturevideo
Related Solutions
So, I ran some Cinebench R11.5 benchmarks to get more information about the single threaded performance of my i5-3427U1 (1.8-2.8 GHz) CPU:
1 thread → 1.10
I also contacted the author of the linked article by AnandTech - @anandshimpi2. Anand Lal Shimpi was so kind to send me a benchark chart which compared the single threaded performance of the 2011 13" Macbook Airs with the 2012 13" Macbook Airs using Cinebench R11.5.
Into this picture, I have added information about the maximum single threaded CPU clocks along with a comparison of the measured performance such as Anand Lal Shimpi has suggested.
In this info graphic I am comparing specifically:
- 2011 13" Macbook Air, i5-2557M 1.7GHz/2.4GHz/2.7GHz
- 2012 13" Macbook Air, i5-3427U 1.8GHz/2.6GHz/2.8GHz
As you can see, the single threaded clock of the 2012 model is 3.7% increased in turbo boost mode.
However, the benchmark score saw a 9.9% increase which is not simply due to the higher clock, but also due to the more efficient Ivy Bridge architecture which is about 5-15% faster3 than Sandy Bridge.
In sum, the benchmark scores are as expected whereas the Turbo Ratios log entries are not. Anand Lal Shimpi had "figured it was a bug, submitted it to Apple back in July"4.
There are two likely issues afoot here:
- Your System Management Controller has gotten some corruption.
- You're seeing potential hardware-/sensor failures.
To reset your SMC, follow these instructions: http://support.apple.com/kb/HT3964
If that doesn't solve the problem, I'd run Apple Diagnostics and see whether it picks up on any hardware problems. If it does, the system should be taken to Apple or an Apple-authorized repair centre for further testing and repair.
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Best Answer
MacBooks do indeed tend to have some issues with their thermals. What I'd try to do in your case would be downloading an App to control your fan speed like Macs fan control. It's free, you don't have to buy the paid (donate) version. You can set your fans to spin up higher than the stock values Apple implements.
Just for testing, you could set the fan to 100% at a CPU temperature of over 70°C and see if it does make a difference in performance.
I also do have a MacBook that's 5 years old now and while I don't do rendering or video conversion like you do on it, I had very high temps aswell just compiling code or browsing some heavy webpages with loads of JS. What I did was open up the laptop and replace the thermal paste. The stock paste that was applied was very badly (see this example from a MacBook Pro 2015). Sadly this seems to be fairly common and while these CPUs do sustain temperatures under 100°C pretty well, the OS often throttles it instead of running the fans on maximum.
Using TG Pro (just a personal preference, the tool linked above does the same thing) and reapplying my thermal paste I went from 60°C in idle to around 38°C and from 90-95°C to 80-85°C under heavy load.
That being said, the computer does get pretty noisy on maximum fan speed and reapplying thermal paste is not something everyone should just try. But the former should be worth a try.