Temperature and CPU Usage
Probably like me, many people experiment with changing various options to get the best result without thrashing the Mac too much. I use a app to monitor the temperature of the system as a guide and have found what I consider to be the best compromise between quality/speed and image format.
I do have one question for the developers though. When I look at activity monitor with Security Spy running is generally runs at about 45% cpu utilisation against that task. I have 4 Axis camera's and the average temperature of my Mac Mini is about 85'c.
Today I've shut down Security Spy as I'm running a program to convert about 100 .avi movies into .mp4 format. The program seems to spawn a separate process and runs 3 concurrent conversions at any one time. Looking at Activity Monitor again I can see each one of these tasks taking about 21% of the CPU which adds up to around 60% in total. In either case nothing else is running on the machine. What has me a little curious is that in this second scenario the temperature of my Mac is 69'c.
All I can think of is that the latter conversion task is not using the network. They are both converting video data. Maybe one of the programs is utilising more that 1 CPU core ?
Bottom line, is there any way to get Security Spy to run on the Mac a little cooler than it does now ?
I do have one question for the developers though. When I look at activity monitor with Security Spy running is generally runs at about 45% cpu utilisation against that task. I have 4 Axis camera's and the average temperature of my Mac Mini is about 85'c.
Today I've shut down Security Spy as I'm running a program to convert about 100 .avi movies into .mp4 format. The program seems to spawn a separate process and runs 3 concurrent conversions at any one time. Looking at Activity Monitor again I can see each one of these tasks taking about 21% of the CPU which adds up to around 60% in total. In either case nothing else is running on the machine. What has me a little curious is that in this second scenario the temperature of my Mac is 69'c.
All I can think of is that the latter conversion task is not using the network. They are both converting video data. Maybe one of the programs is utilising more that 1 CPU core ?
Bottom line, is there any way to get Security Spy to run on the Mac a little cooler than it does now ?
Comments
-
Hi Dave,
The main thing that generates heat in the computer is indeed the CPUs, however other components also generate heat (the RAM, video cards/GPU, power supply, disk drives etc.). It must be the overall profile of resources that SecuritySpy is using that means that more temperature is generated than your simple video encoding software - perhaps it is the video hardware for SecuritySpy's video windows?
SecuritySpy is multi-threaded and will use multiple cores simultaneously for it's compression/decompression tasks, but if your video conversion software spawns separate processes then it is also using multiple cores simultaneously.
A 45% CPU usage isn't very high, especially on a multi-core machine (e.g. if your computer has 4 cores, a 50% CPU usage means that SecuritySpy is using only an eighth of the total processing power available). You could reduce the frame rate of the cameras, or close video windows, or reduce your usage of SecuritySpy's web server, in order to reduce SecuritySpy's resource usage and therefore the temperature, but I don't think there is any need to do this. When the temperature goes up, the Mac's fan speed will increase to compensate.
85C does seem remarkably high though - we use a Mac mini for our surveillance needs and to provide the live demo of SecuritySpy. It has 9 network cameras and runs at 60-80% CPU continuously. All the temperature sensors are in the 50-60C range. Is the fan in your mini particularly noisy or does it sound like it's struggling? If so, it may need replacing.
Hope this helps. -
I have physically cleaned the mac and also reinstalled OSX to eliminate any software issues. In addition I have reduced the frame rate to 5fps and now the Mac Mini is happily running a 65'c
Thanks
Dave
