There are a few ways you can try to speed up SSH X11 forwarding on Linux or Unix:
Use the "-Y" flag when connecting to the remote server. This flag enables trusted X11 forwarding, which may be faster than the untrusted forwarding enabled by the "-X" flag.
Enable compression for your SSH connection. You can do this by adding the "-C" flag when connecting to the remote server. This will compress the data being transferred over the connection, which may improve performance.
Use a faster network connection, such as a wired Ethernet connection instead of a wireless connection.
Increase the amount of memory and CPU resources available to the remote server. This can help to improve the performance of the X11 forwarding.
Use a lightweight window manager on the remote server. This can help to reduce the load on the server and improve the performance of the X11 forwarding.
Consider using a different protocol for X11 forwarding, such as VNC or RDP, which may be faster than the default X11 forwarding provided by SSH.
It's worth noting that the performance of X11 forwarding can also be affected by factors such as the speed of the local and remote computers, the network connection between the two, and the complexity of the graphical applications being run.