Basically, whichever video card I set to 'Screen 0' in my XF86Config file will get 3D acceleration, and the other will not (e.g. if I drag, say the Quake3 window, to the second screen, the window will just be blank).

Now I'm starting to get the idea that XFree86 doesn't support this, so if this is the case do alternatives such as X.org support it?

Edit: Support for both screens to have 3D acceleration at the same time, is what I mean by 'support'.

Both of my video cards are nvidia - an AGP GeForce4, and a PCI TNT2.

In windows i get the same thing (havent installed ati drivers in linux yet). I think it's that the card only supports openGL on one monitor at a time. I have a radeon 9600 256MB, it might be ati, they have pretty crappy multi monitor support from what i've seen.

I'm having this issue too. Anything with OpenGL will only work on monitor 1.

I have an ATI 9600 card also and run two monitors with it, both in Windows XP and in Fedora Core 3. I can run with 3d accelleration with both screens in XP (so I know the video card supports this); but in linux, only the first screen works right. For example, trying to run any of the OpenGL screen savers will show the screen saver (left half only) on the left screen, but the right screen is black and stays that way.

I considered putting ATI's drivers for linux on my system, but ATI only shows drivers for XFree86, and Fedora Core runs Xorg; so that won't work.

I keep thinking there has got to be a setting in the xorg.conf file that I can change to get the OpenGL to work on both screens in Linux as it does in XP, but I may be barking up the wrong tree. I also upgraded with up2date to get all the latest versions of all the xorg software.

If anyone comes up with the solution to this (openGL only working on the first screen in a dual head system), i would also be very appreciative! Also, if I figure this out, I'll be sure to post the solution too.