HP Laserjet 4000

I installed a HP jetdirect 610n internal printer server into a HP Laserjet 4000 printer. I assigned a static IP address the print server. If I print a configuration page directly from the printer, the page prints very quickly. If I send a job to the printer via IP printing, the printer receives the job very quickly put processes it very slowly. The paper seems to crawl through the printer and exits very slowly. The printer only had 4 mb of memory, so I added 32mbs. The additional memorydid not resolve the slow speed.