Meaning, when lots of text goes by, it all gets saved to your screen and will tend to slow everything down. You should be able to set this on your client to only retain a few pages, or whatever works for you.

If the symptom is you keep getting slower and slower the longer you stay on, then this is most likely your issue.

For instance, I have an option on my client to "clear scrollback buffer", which makes things go oh so snappy when it starts to get slow.