[digiology]

I use this old screen 15" from an old Pentium 1, the recommended resolution in the OS X preferences is 800x600 60Hz. If I change to anything over 1024x768 the screen goes garbled. Or if I set it over 60Hz it goes garbled.
When I start the Giants demo, or the Return to castle wolfenstein demo the screen goes garbled in a simular way. But the Quake Arena demo works ok. Is it the screen or the graphics card, or a software issue?
Im using a Dual 1Ghz G4 with a GeForce4. Please help me!!!!

[mac freak]

Frankly, if you're using a dual GHz G4, you can afford to buy a cheap new 17" CRT for like $150. It will be worth it in the long run!

It sounds like the monitor you're using is so old that your video card simply doesn't support it.