Game & all video renders well.
(PLP screenshot with bezel effect)
1. SoftTH (DX9 x86).
2. In regedit, Find (Ctrl+F) "Forgotten Sands" in Keys only. Looking for ...\Software\Ubisoft\Prince of Persia - The Forgotten Sands\#.#\Engine. Ignore any other hits.
3. Edit values of Engine key (in Decimal Base): AspectRatioOverride ### ([your width / height] x 100, rounded to three digits); for ScreenResolutionWidth & ...Height, enter your massive resolution (####, no border).
4. HUD & Text Fix (optional, recommended): looks good, except greatly reduces menu size. In regedit, same Engine key: modify value Eyefinity to 1, Exit.
NOTES:
A. Upon quitting game, it may abend & error message. Not a problem.
B. If you get stuck after death at a door you can't get past, trainer by h4x0r apparently fixes it (untested, & probably not steam).
(rendered video)
View guide for general help with the instructions.