Try setting DOSBox to use a different video mode for fullscreen? You may also want to make sure it's using a proper refresh rate for the mode you're running in, although I couldn't say how to do that as it depends on your hardware and OS.

I tried all the different modes with the same results, works fine when not in fullscreen mode.

Incidentally everything works perfectly fine on my laptop (AMD 64 3400+ w/ Radeon 9700) which makes me wonder if the problem is being caused by my video card on my desktop (P4 3.2 w/ nVidia 6800GT) -- both my laptop and desktop are running on Windows XP.

Does overclocking create problems with Dosbox? Both my CPU and video card are overclocked (on my desktop) so that may be a possibility. Any other suggestions would be great.

try fullfixed=true in dosbox.conf

Ok that did the trick, no more jittering.

What resolution should I set it at so when I go into fullscreen mode using fullfixed it uses up the whole screen? I tried 640x480 but it seems to be stretched oddly and cut off at the top.

I have problems in full screen too. If I start DOSBox with fullscreen=true it crash. I can see the DOSBox black screen and the letters but it don't work.
If I start DOSBox in normal window mode it works fine and sometimes it works when I press Alt-Enter to go to fullscreen mode, but if I change to another aplication or a dialog box appears then DOSBox is minimized and I can't restore it again.
I tried with fullfixed option but remains the same problem.
I'm running WinXP

Thanks!

I have a problem with fullscreen as well. It could be that I'm just stupid or whatever, but I can't get dosbox to STAY in fullscreen. Even if I tell it 'fullscreen=true' it'll just leave immediately. It's basically as if it keeps alt+tabbing out automatically. Sometimes it stays for a few seconds then alt+tabs out again, sometimes it doesnt even show anything, just goes black and before it shows the dosbox contents it just returns to windows again. In the rare case that I do manage to get into fullscreen properly, there is no trouble at all, fullscreen works just fine and never leaves on it's own accord. That is, until my virusscan nags about updates or someone IMs me, and it alt+tabs out, then I can look forward to another 10 minutes of frustration and f***ing about before I manage to get it to STAY in full screen again. (I have a feeling it's mouse-related though I have no indication whatsoever if this is indeed so.)

Help/suggestions, greatly appreciated. On a sidenote, GREAT piece of software... finally get to relive the olden days of 10+ years ago 😄