Remote desktop develops mouse/keyboard lag after some duration
Solution 1:
I have experienced a similar problem. I have a Remote Desktop Connection from a Win7 client to a Surface Pro 3 (SPro3) running Win 10 anniversary OS.
(NOTE Prior to the anniversary update I had sleep options which are no longer available - running powercfg /a from an elevated CMD window shows that sleep in not supported with the current firmware version).
I have the SPro3 configured to turn off the display after 15 min (I assume this also invokes some type of sleep mode). As long as the display on the SPro3 is ON the keystroke and mouse operations from the client to the SPro3 respond in a reasonable fashion. When the display on the SPro3 turns OFF response fro keystrokes and mouse movements are delayed slightly. Touching the SPro3 screen turning the display ON resolves the problem until the display is turned OFF again. I have also noticed when the display is turned OFF on the SPro3 running the task manager from the client the CPU activity is about 12% to 15% compared to 1% to 2% when the display is ON.
I should further note in the same configuration with the SPro3 running Win 8.1 and sleep properly configured (this took a while to configure and my notes are not clear) this problem didn't exist.
Solution 2:
This is also present on Intel NUC with Windows 10. Try setting Put display to sleep after to Never in "Power & Sleep settings".
Solution 3:
@RichardH's answer worked for me too, but I like to keep my laptop lid closed while I'm remoted into it.
I found that running Chrome Remote Desktop (CRD) alongside RDP fixed the issue for me too. After installing CRD on the remote laptop and the local desktop, connect to the remote laptop using CRD so that the login screen shows. You don't need to login, just keep the CRD window open (not minimized). Then you can connect normally with Windows RDP and lag should not be present.
I also noticed about a 3% increase in the "System" process CPU usage when the lid was open but turned off compared to when it was open and on.
This only started for me after installing the Anniversary Update.