Quote Originally Posted by Multibocks View Post
So would you recommend dx11 for a two monitor setup on a GTX 680 for 10 accounts or dx9? One computer
The number of monitors you use and the number of computers you use is pretty much personal preference. To get the most accurate answer/result to your question you're going to have to test out the differences between DX9 and DX11 for yourself to see how your system handles them.

If WoW only had one static set of video options and there was only one type of video card in the market, then the answer would be much more straightforward. Some people like to play with their Shadows turned up while others like their Shadows turned down and their View Distance turned up. Some people like to turn up Ground Clutter so that the ground looks more populated with flora for a more realistic look, and some people like their Environmental Detail turned up so that they can see objects like fences further off in the distance.

Also, if each of your game clients is running at the exact same resolution (e.g. ISBoxer's Instant Swapping is enabled), then that's going to impact performance as well. 1280x720? 1920x1080? 2560x1600? Resolution plays a large part in the stress that's put on a CPU/GPU while processing what is on the screen(s).

There are so many factors (both in and out of the game) and every single slider in WoW's video settings is going to use a part of your CPU or GPU in some way, shape, or fashion. I've been meaning to build a FAQ-like sticky for this forum to help answer questions like these, but I've really been slacking lately.