Lagging RDP session - Windows 11

Performance issues are often very hard to find a cause, and I’m sure everyone wants to blame the proxy.  Before you write off Windows 11, note that this OS will enable UDP for RDP by default, which can cause unnecessary packet retries.  Be sure usage of UDP for RDP connections is disabled across your enterprise (registry/GPO).  Next, check network latency from client IP ranges to proxy, then check proxy to various target/managed systems.  Next, check performance of the BI proxy itself.  Do you have session recording enabled?  What is the I/O wait of your servers/VM?  Do you have dedicated Password safe node(s) that are not competing for CPU with the admin node?

Also, do you have similar issues with SSH connections (or SFTP transfers)?  If not, the problem may be RDP specific.  If so, then it’s the network or proxy itself.

Hello ​@MichaelF,

Thank you for your comment.

I forgot to mention in this thread that the issue doesn't only affect Windows 11. I've also seen this behavior on other colleagues' Windows 10.

However, many of them didn't report this as a problem because they thought the slowdown was normal due to RDP access. We know that RDP can have some standard slowdowns.
However, we've often noticed severe slowdowns, beyond the expected RDP protocol.
This behavior is significantly worse considering users we have outside of Brazil, in other countries.

During these times of severe slowdowns, I monitored the proxy server resources, and all were at less than 30% utilization.
I/O was fine, and network consumption was very low, well above the server adapters' limits.

With some information from the Knowledge Base and after contacting support, I understood that Password Safe uses the Bitmap codec as the default for images. Some research shows that Bitmap is an uncompressed codec that consumes a lot of network bandwidth and can suffer from low-speed or high-latency connections.
However, our connections have good speeds and low latency, and we still experience slow access.

Using the gfx and gfx_caps_override registry keys mentioned here, Password Safe now uses the H264 codec, which has an excellent compression ratio without losing image quality.
And with H264, everything works perfectly even for users in other countries, far from the data centers where the servers are hosted.
But it's not all sunshine and roses. H264 caused us problems when accessing some older servers that don't support this codec, and we also lost the session loading screen, which was replaced by a black screen before the server image was displayed.
So, I can't convert the entire environment to H264 right now.

I would like to thank ​@Paulo144  for the help on this case. With his help I was able to test and notice this same slowness in his test environment with default bitmap codec.

I think it would be great if FreeRDP had a way to negotiate the best codec during the RDP session connection.
But I also imagine that the Bitmap option is necessary for the entire solution to work, even if it works with H264.

I'm still trying to find a way to solve or at least improve the slowness in our environment.

This behavior is significantly worse considering users we have outside of Brazil, in other countries.

There’s no way to increase the speed of light (the internet).  RDP was designed to be a LAN protocol, not connect over the whole world. Anything above ~150ms latency and the connection is not stable.  Use a solution such as PRA for users accessing RDP sessions across the world.