>>I finally figured it out! It turns out that the default for a LaserJet 4 is 600 DPI while for the LaserJet 3 it is only 300 DPI. When I set the 4 to 300 DPI the speed increased to that of the LJ 3 (although the quality of gray shading was lower than for 600 DPI, but for this app that's not a big deal).
>
>You must be printing a lot of graphics. For regular print jobs (i.e. text) a LJ4 will print at 600dpi as fast or faster than an LJ3 at 300dpi. In fact, the later-model LJ4+ was rated at 12ppm vs. 8ppm for the 3/4.
>
>You still might want to look into your printer/network configuration. If you've got a 10 or 100Mbit connection to the printer you shouldn't notice any difference between 300 and 600dpi unless you're really pounding it with graphics.

I am printing a regular report where I print a grey bar behind 3 detail lines at a time and then off for 3 lines, thus simulating the old-fashioned "green bar" paper that the system this is replacing used to use. I am using a basic LJ4 (not the plus). The output is visibly different between the two resolutions where the grey bars are much smoother at 600 DPI (as you might expect) than at 300 DPI. As far as consulting our network administrators we are kind of our own administrators where we know just enough to keep our isolated network of 5 computers working. All I know is when I changed the resolution setting on the LJ4 printer configuration the speed jumped back to where a LJIII is. With 600 DPI it would take about 30-40 seconds per page while at 300 DPI the pages come out as fast as the printer can spit them out. Thanks for all the helpful suggestions.