Hello,
This is patch which shows fps counter in upper left corner of the screen. You can enable / disable it with F12 key. It's disabled by default.
Patch was created from src directory.
Btw, last time i programmed in c/c++ couple of years ago. And even then i didn't code much in it, so this can be buggy
Also, i'm not sure if it shows correct results.
My results (ubuntu linux, Intel(R) Pentium(R) Dual CPU T2370 @ 1.73GHz) at 640 x 400:
Main menu: 150 - 160
Geoscape (doing nothing): 110 - 120
Geoscape (rotating on min zoom): 60 - 90
Geoscape (rotating on max zoom): 50 - 70
Battlescape (doing nothing): 140 - 150
Battlescape (scrolling): 135 - 140