I have found this forum when I was searching for a low fps fix. I have tried that big VBS scirpt, but it didn't work for me (empty window with sound only appeared). I know that low fps is related with DirectDraw emulation in Windows 8 and higher, so I've decided to search for ddraw.dll patchez. There are many of them but every package workz differently and some gamez cannot be fixed by this way.
Eventually I have found the perfect solution, which workz perfectly with Gruntz and now I can play one of my most favourite games.
Here'z link to ddraw.dll library appropriate for Gruntz: