UltraVNC Keyboard Lag (Latency)

[sbonds]

I'm using UltraVNC in an ideal network environment-- the client and server are both Windows 10 and are on the same gigabit local LAN subnet. When using "Ultra" everything looks beautiful. There are no compression artifacts and I'm very pleased with how it works... except for the keyboard lag. When I type anything, there is about a 0.2-0.4 second delay between the typing and when the characters appear. This does not happen when using RDP, but RDP has... other issues which necessitate using a tool like UltraVNC.

I can see that the keypresses arrive since a local screen set up on the client shows them appear. The delay is between when they appear and when they arrive back at the UltraVNC client.

What should I check to improve the latency issue?

[Rudi De Vos]

Try to set the encoder manual + mouse method ( server/viewer handled)

(compression time + network time + decompression) + network latency
Higher compression takes more time, but decrease the network time
Less compression is faster but use mor bandwidth.
Latency is a combination off all.

[sbonds]

I ended up changing the server properties and checked "Desktop Duplication (restart on change required)". The documentation on this seems absent, but I did see a couple of threads mentioning that Windows 10 worked well in this non-default config. Turning that on seems to have fixed the latency issue.

Since this is on a local, high-throughput, low-latency network, my goal is for the compression to get out of the way and just send a fire hose full of data back to me.

[Dishair]

I want to confirm that "Desktop Duplication" Settings change resolves the problem with input lag on Windows 10 (VNC server).