I have a mystery. I am using ffmpeg.exe to convert videos to frames. On most machines I get very good speed. On an i7 I get 144fps. On an old Core 2 Duo machine I get 75fps.
But weirdly on an fairly new i3 (4 core) I get 30fps or less.
I have run these tests using exactly the same version of ffmpeg and the same video file.
All machines are Windows 7, all have 4 GB ram. I'm trying to understand why the i3 is so slow for FFMpeg. All other applications seem to run fine. No memory problems I know of. The virus scanner is the same on all machines - MS Security Essentials.
The only difference I can think of is the i3 machine has truecrypt. But I don't see why it would have an impact.
What am I not thinking of? Graphics card?