Just an update, now have it running under Directx 11, Windows 8.1 64bit, took a lot of mucking around but after a ton of programming it now runs smooth. Why they didnt just release a patch to make it compatible is beyond me.

SH4 runs smoothly as well.

SH5 on the other hand, went straight to the recycle bin.

Wow! Sorry I didn't read this earlier. I've been playing SH3+GWX, SH4 and SH5 on Windows 7 64-bit for years now with DX 11. Don't know where this "you gotta have DX 9c" comes from.

My SH3 doesn't run at just any resolution, but the NVIDIA graphics engine tells me that before the game even loads. For example, my monitor is 1920x1200, but the highest resolution I can get the game to run full screen is at 1600x1200, which is not that bad -- slight vertical compression, which I don't even notice any more. Part of this is graphics card vs. monitor resolution capabilities.

Also, since Vista, it has been recommended that you not install in the "Program File (x86)" directory -- program has had some problems there. I install in a "c:\Ubisoft" directory. I also turn UAC off first thing when I get a new computer. Another standard recommendation is set SH3.exe Properties > Compatibility to "Windows XP (Service Pack 3) and "Run as administrator".

I have heard of problems with the STEAM version of the game, but I don't own that version. I'm sure that issue is mentioned here in many other places.