I have been using handbrake to convert my dvd collection, but found that I can’t really use my computer effectively for much else while it is using 100% CPU, even with the thread priority set to Low.

On each item you can manage the CPU affinity manually through task manager, but when you have 10-20 conversions queued up you have to constantly manage each new instance of the HandbrakeCLI as it works through the queue.

The solution is to select your preferred preset, in my case “Apple Tv 2″ ¬† and in the open field on the advanced tab, add the following text

:threads=1

You could also use :threads=2 or more, but on my core I7-860, I found that 1 thread uses about 25% of my CPU power, which works well when I am doing other work (or gaming) on my PC while converting my DVDs to x264 in the background.

Then ¬†just save the modified profile as “Apple TV 2 – Low CPU” and set it as the default.

Problem solved.