If you want to modify additional settings, go ahead and open it in your favorite editor:
You’ll notice a lot of settings separated into different sections. Most of them are already fine. You only should change a few things:
The [sdl] section
fullscreen=true if you want DOSBox to start in fullscreen;
output=overlay if you got an accelerated graphic card (that’s the case of modern systems), otherwise keep it at surface.
The [dosbox] section
If your games abort in case of insufficient memory, increase the value at memsize. Keep in mind that this value is meant in MB and will be catched from your real memory, so don’t set it too high. In most cases the default value works fine.
Don’t forget to set captures= to the path, where you want to store your captured videos, screenshots and wave files, for example: captures=D:\mystuff\dosbox\captures\.
The [cpu] section
core=dynamic and cycles=max to get the best performance in most cases. If DOSBox runs badly with these settings, try to set core=auto instead. In case your game runs too fast or choppy, try a numeric cycles value like cycles=3000.
The [render] section
If you got a slow PC, you can increase the speed by setting frameskip=1. DOSBox will skip a frame before drawing one. That means, you’ll see 35 fps instead of 70 fps, but you get more CPU power for the plain emulation. This option only affects DOSBox itself, you don’t influence the games’ own framerate directly.
The [dos] section
In case you use a non-US keyboard layout, which is often the case outside the USA, it makes sense to adjust the layout in DOSBox. To do this, just set the country code behind keyboardlayout, for example keyboardlayout=de for Germany. You can get a list of country codes at the DOSBox Wiki.
The [autoexec] section
If you used DOS before, you’ll probably remember the AUTOEXEC.BAT file. It included the commands which were started at boot time. In this section, every command will be executed when DOSBox starts – like the AUTOEXEC.BAT file did. At least, it should contain the following lines (you can add more if you want):
mount c "D:\mystuff\DOS games\"
(this will mount your games folder as drive C: in DOSBox)
mount d E:\ -t cdrom
(this will mount your CD/DVD drive E: as drive D: in DOSBox)
These are the most common settings. You can get more at the DOSBox Wiki.