I have a Viewsonic P75f and it is not supported.
I set it up as Vesa 1024 x 768 and entered the hf and vf.
However, whenever I go back in yast a get a message that the monitor is not installed.

I am not able to play 3D games so I enabled 3D.
When I start Tux racer my screen goes black and my monitor gives me a message that the hf has been exceeded.

I decided to try and solve the monitor not installed issue by choosing a P95f which is supported and change the hf and vf setting so they match the P75f. I went back into yast and it worked and see the monitor as P95f. Then I tried Tux racer again and it works.

Since I did the monitor change my image on the screen was smallar than the screen size so I adjusted by zooming in abit to fix that. However, now the 3D games don't work again and I get the same message form my monitor that hf has been exceeded.

did you set the hf and vf rates for all color depths like 8 bit 16 bit ...?
If you cant manage it using sax2, try to get as much as possible working and do the rest of the configuration in the xf86config file. I think the section where the monitor is defined is called [Display]. Although i'm at my job at the moment, i'm working on Loosedows :-( and can't look it up. You should look for a String with the Name the Monitor has in sax2 to find the appropiate section.
Regards Maddie

That sounds good.

Since my default setting is 1024 x 768 it doesn't mean that the games play at that res.