CPU usage

[rakader]

Hi guys,

I have big problem with CPU usage on an iMac 27'' with i7 and 32GB RAM running on macOS 10.12 with Handbrake 1.0.2

I tried to manipulate the deprecated Advanced Options, setting up the h264 option string - withou result, i.e. threads=1. Acitivity monitor reports up to 768% usage of CPU. This can damage my computer.

Is there a solution for this problem?

Cheers
Radulph

[s55]

Threads only affects x264 threads, not HandBrake threads which you have no control over.

High CPU usage is not bad. HandBrake is designed to use as much of the CPU as it can. Your hardware should cope with it just fine. If there are any cooling issues, Intel CPU's lower their clock speeds to run cooler anyway, so it's a non-issue.

[mduell]

Acitivity monitor reports up to 768% usage of CPU. This can damage my computer.

Doubt it. If so, your computer is defective.

[Woodstock]

A 2011 or later iMac 27" with clean cooling paths can handle 100% CPU for long periods of time. If the paths aren't clean, temps will climb enough that the system will give you a warning and start cranking back the speed to protect itself.

[LowTech]

You can use cputhrottle from http://www.willnolan.com/cputhrottle/cputhrottle.html

The binary is for OS X 10.5 but it still works on 10.12.

[kahutafkar]

throttling the CPU usage is just what I want to do, mainly so I can use other apps while using Handbrake. However, I have limited experience using the terminal and I wasn't clear on the instructions in the linked item. Would you not recommend this path to an inexperienced user, or can you advise on how I can clarify things?

[roundy]

Also, you are miss-reading what Activity Monitor is telling you. Yes, it does say that CPU usage is at 768%, but that's not what it means. You are not running your entire CPU at nearly 8x's maximum capacity. What it means is that each thread is running at 96% x 8 threads. You have the i7 chip which has 4 cores and each core can run 2 threads. So you are running 8 threads at 96% for each thread. Activity Monitor reports this as 768%.

Another way to look at it is the maximum that your CPU can run is 800% (as reported by Activity Monitor).

FYI, I just started a Handbrake convert to test and Activity Monitor reports that Handbrake is running at 1,108.8% CPU. I have a 6 core Mac Pro, so that's really 12 threads. So each thread is running at 92%.

[Ronin]

Its not a problem, high CPU utilization is what is expected when the CPUs are tackling a touch job like transcoding. The Mac will lower the CPU speeds and increase the fan speeds to keep everything in the safe zone, so there s nothing to worry about. If there is an issue then the system will automatically shut itself down, so it can cool off.

One thing I have experimented with is an app called TG Pro. It allows you to see the real time temperature of all your sensors so you will know exactly how hot all the components are. In my experiments I found that if I spun up the fans to max speed before I started the Handbrake job (TG Pro has fan speed control capability) that the CPUs tend to run cooler. I don't know why that would be the case and have tested it dozens of times and it still works for me.