Q I run a stripped-down version of Windows 7 under Fusion VMWare to use Proshow Producer, then load movies into iMovie, which runs exceedingly slowly. How can I strip OS X down to improve iMovie’s performance?
A Windows and OS X work very differently, and there is no simple way to further optimise the performance of OS X by reducing what there is of it.
You can strip out language localisations to free up disk space, and certainly you should ensure that you are running a minimum of third party ‘enhancements’ that have a propensity to soak up processor time. OS X works best, and iMovie works fastest, with plenty of memory, so you should install that maximum that your Mac can use. It also makes best use of as many processor cores available, although that is fixed according to model.
Ample contiguous free disk space helps, so ensure that you have at least 100 GB available, more than 500 GB if possible. If necessary it is still possible to defragment free space by cloning your boot drive to an external disk, restarting from that, then cloning it back again. As well as defragmenting all the files on your hard disk, this puts all the free disk space into a single contiguous block, which ensures that virtual memory and scratch files are readily allocated and perform well.
You can also use Activity Monitor to see if there are any other processes burning up processor power.
For movie processing, you may find it preferable to upgrade to Apple’s Final Cut Pro suite, including Compressor, which is intended for heavyweight and pro use. Although iMovie is an excellent tool, it is mainly aimed at the consumer market, and Compressor will give you better encoding and transcoding options that should save time.
Updated from the original, which was first published in MacUser volume 27 issue 14, 2011.