Vince:
This should not be the case. I followed the relevant OpenGL specification; windows-specific requirements are a big no-no, although I certainly wouldn't be very surprised if one exists.
Lacking (hard/soft)ware that does this, however, there really no useful way I can debug it. It would be nice if you could figure out what's going on, but really, standard mode should be more than good enough on that hardware.
Sir Prinny:
The partial-print number is the number of times a given tile is redrawn before we stop, after it has been changed.
The reason it exists is that the SDL window DF asks for is, by default, double-buffered. This means there are two areas in video memory for it; we draw to one, while the other is displayed, and they are then swapped.
Turning on single-buffering changes that to, well, a single buffer; if this works (which it very often doesn't, except on old hardware), only one drawing is required, which you get by setting redraw count to 0.
You should normally not need more than 1. However, for situations such as triple buffering, 2 may be needed. That said..
Modern GPUs often have far more than three buffers, and old ones may be overwritten with random data before going back on the top. In that case, you may need a large number - in which case the performance goes to hell - or partial printing simply won't work at all. Dealing with this problem is what the Accum and Frame_buffer modes are for, as both emulate single buffering.