Prntr on A/Bswitch working slowly one PC

I have 2 identical Compaq Deskpro EP330’s that share a hp deskjet printer via an Belkin electronic A/B switch. One PC prints fine, just like it had the printer attached directly to its parallel port. The other prints very slowly. It takes 15 minutesto print one page. The Belkin website suggested disabling the bi-directional communication that HP likes its printers to do. I have disabled it both in Windows and in the BIOS. I have downloaded updated drivers for corporate users, leaving out all the proprietary garbage hp includes on its cd. Any ideas on how to make the second PC print normally?