Serial port COM1 is very slow with XP verses ME - Help !!

I purchased a new computer today (emachine 2.8 ghz)
running XP (downloaded & installed the updates). My old
computer is a (emachine 667 mhz) running ME. I use a
serial printer for a special application, it uses the
serial port ( COM1 ). Moved my software over to the new
XP machine and everything is great until I try to print.
The printing is extemely slow ( 1/4 the speed !! ), the
printer waits for the computer. With ME on the old system
the computer dumped the data quick (is there a buffer
somewhere) and went back to the program, meanwhile the
printer tryed to catch up.
Any help is very much appreciated
Thank you