Are your two computers networked? You should have the second computer be your print server. The second computer would simply store the print jobs in a spool file and then print as the printer is available. That way your main workstation machine is not bogged down by having to store those large print jobs in memory.
Have a new Dell 4600, 512 ram, XP Home. I bought that much ram because I thought it would help printer ram usage. Using an Epson stylus color 900 because it is good for normal (bookkeeping) and have to print ALOT of digital photos (for business). The computer uses most of it's memory while printing photos--can't do other work (no better than my old computer with 256 ram). I will be having to buy another computer (hopefully cheap) to work with a HP Series 430 plotter and to print same photos. What do I need to buy to improve speed (printing blueprints) and ram usage?