Just finished setting up my SP3 with a Dock and 3 External screens running off the Dock displayport output. It was not something I was entirely sure you could do, but you can move your primary screen to one of the externals and then turn off the SP3 screen. Without turning off the SP3 screen the computer will see all 4 screens but only let you run 3. The exact setup I have is SP3 i7->Dock->Mini Displayport to Displayport cable->EVGA DP Hub-> Dell U2711 (primary) |> Dell U2412M |> Dell U2412M (portrait) I don't seem to be having any problems with the resolution, and interestingly enough, the fan didn't kick in while streaming a video like it always does on my 2 screen setup at the walking desk. My primary goal here is to replace my desktop completely, using the SP3 at both my desk and my walking desk. This will seeming work fine, although I will still need some additional storage at my desk, and perhaps a USB DVD reader. In the end, I may wind up using a USB 3 dock to drive the 3rd screen and recover the SP3 screen as well. I have one that I can move over. The SP3 has, so far, exceeded every expectation I have had.