It's a printer and not a PC would be the likely cause, not exactly state of the art web browser built into it.
I have an entire lab full of MFP's at my disposal, what printers are you running that work so much faster with these identical remote applications? I'm interested since I haven't noticed any speed difference between say an older 7556, or an XC560, or a 7435 and any of the Connectkey family for accessing eCopy or Equitrac, but I haven't gotten a stop watch out either.