Some time ago I got new PC with Windows 8.1. It was quite powerful (8 cores and 32Gb of memory), however I faced with unpleasant issue: over RDP it was very slow. Especially slow was Outlook 2013. It hang after each mouse click and working with it was quite painful.
I tried to check what may be wrong. Need to say that I use RDP over UAG, i.e. couldn’t change RDP properties like display size, color depth or optimize connection experience (those things which you may do when it is possible to save RDP icon to the desktop). So several possible directions of investigations were excluded automatically. The first thing which I tried was disabling of taskbar transparency which may cause problems with performance. In order to do it I used found Opaque Taskbar utility, however it didn’t give results. RDP still was very slow.
After that I tried another solution which I found in one of the forums: ran cmd as administrator and execute the following command:
netsh interface tcp set global autotuning=disabled
which supposed to disable TCP/IP auto tuning. And it solved the problem. After that Outlook 2013 started to work very fast over RDP and overall RDP performance was significantly improved.