I don't think Zipper is right (but you never know) WHDload usually handles all the caches appropriately for a particular game.
The most likely thing is you've originally played it in PAL and the slave has the NTSC tooltype set. Games running at 60Hz will seem a bit faster than 50Hz (obviously)
Check the game icon's tooltype for an NTSC entry and if it is there remove it, if not try adding the "PAL" one.
If that does not work you can try what Zipper suggested and add to the icon's tooltype the "NoCache" option.
http://www.whdload.de/docs/en/opt.htmlIf you do not know what a tooltype is then... erm... look it up?
