For several months, my WebMin CP was virtually dead due to the bandwidth shaping Maxnet was doing. I'm talking 10 minutes just to get to a real functioning screen. I talked to my host about the problem and they created access to it on by additional port. It was on 4xxx and now it's also on 4xx

Now it's faaaaaaast!!! I can screw up my server without any help from my host support team!

I shudder to think how slow CPanel would load on port 4xxx

So maybe talk to your hosting company.

My Cpanels are at port 2082, and are indeed slower then regular used ports (http etc).

However it's still usable!

Does it get even worse on higher ports? My servers are part of an HSphere and the HS CP was on 1XXXX. The new port is 4XX and the difference is just as remarkable .. maybe more so.