the performance to logon the sap from taiwan to shanghai is poor

Hi:

the customers in taiwan loggon the PORTAL integrated CRM and BW in shanghai with the INTERNET. The TAIWAN custom 's speed connected to INTERNET is 4M/4M and the SHANGHAI network speed connected to INTERNET is 4M/4M. The FTP speed including downloading data and uploading data is 350K/bps and 52k/bps from TAIWAN to SHANGHAI.

But the time to load the HTMLGUI in the PORTAL is about 3~5 minites,even 7 to 10 minites,the performance is very poor.

Why? who have the experiences about this and how to improve the performance?

THAKS.