That is an oddity, can you reproduce it on more than one PC/Mac?
It sounds like some sort of driver corruption, so if it is on more than one PC I would think it relates to a driver shared out by a server. But that is just guessing.
You could try modifying the existing driver to match the following setup and see, but I think total removal and reinstall the latest (I'd go with the Global PS ) driver.
The defaults for drivers are typically not the best, so the following are screenshots of things in Printer Properties that should be changed from the defaults for any Xerox device, and honestly, pretty much any other manufacturer with exception of the specific queue name in LPR
Intense files that are not formatted for print (Layered, transparencies, odd fonts improperly embedded in a non PDF/x standard) tend to be much slower, especially when printed through a shared print driver. The things I have shown here will still apply, but won't make as drastic of a change in that scenario. The issue there is always the Bi-directional transfer getting slowed by the Client>Server>MFP>Server>Client transfer during every interaction. Add to that there is another lag when cross architecture ala an x86 PC and a 64Bit server.
That requires disabling Bi-Di, which is crappy as it means the driver does not know how much toner is left or what paper is loaded.
