RDP access very slow, repeated issue

Our RDP became really slow for all our users so I changed the default port with a forward on our router (after attempting various other fixes).

Therefore to connect users were using External-IP:5432 translated by the router to 192.168.1.49), after 2 months we unfortunately had the same issue occur.

This is not a computer speed issue, the CPU usage is not normally over 30%.

I then changed the port again but in the server's registry instead (ie it was newly set to 1998 instead of 3389, so users connected using External-IP:1998 translated by the router to 192.168.1.49:1998. That was fine for another 2-3 months, again but the same issue occurred.

I reset the windows registry port to 3389 and I have now got the router open on port 3334 (External-IP:3334 translated by the router to 192.168.1.49) and 3389 (External-IP translated by the router to 192.168.1.49), they currently both work fine but the other port is still slow (5432), anyone have any ideas why this is happening?

I really hope this doesn’t happen again!

PS we have upgraded and changed router to solve this issue, and this issue even re-occurred after we moved offices!

Please help!

Thanks
Anthony