Thanks for the note.
I brought this week 2 USB monitors and I use them for MFD's. The problem was that my FPS drop from 60-70 avg to 20-30 avg.
I use DisplayLink for the USB monitors.
After I install the new beta driver 270.51 I have return to 50-60 FPS avg.
It's amazing, try it guys!
Thanks man, I can enjoy now from my DCS+2 MFD's with minimal FPS lose :)
Edit: Nope it's not help I found the problem.