First up check out this link: http://xtiming.sourceforge.net/cgi-bin/xtiming.pl
Its a modeline generator, very handy for setting custom screen modes and refresh rates for the xorg.conf file (who needs powerstrip
Anyway, what I need to know from fellow slack users is the lowest screen res you can run. The lowest I can is 512x384, anything lower and the Xorg log reports a "bad mode clock/interlace/doublescan" error.
Typing 320x240 into the above link gave the following modeline:
Modeline "320x240@85d" 17.99 320 352 384 416 240 244 248 253 doublescan
I think the trouble is that the "doublescan" function (which is essential for low res modes) has been disabled in Xorg or possibly not supported on some chipsets (I use a Matrox G550). Can anyone verify this?