Thanks for the reply.
After a bit of investigating i have realised that all my emulators have the same aspect ratio as mame so i dont think its mame related.
My main windows deskop displays fine and maximus displays fine too so im not too sure whats going on.
I think i will try and get the monitor adjusted to display the emulators fine (im using snes,nes,sega,mame,zinc,nulldc,epsxe) and then figure out a way of adjusting maximus and windows.