[trombel]

As a matter of fact, everytime a tried the command Xorg -configure, the driver used in xorg.conf.new is always vesa, not s3.
My video card does not support 1920x1080 resolution. It has only 8Mb.
I substituted vesa for s3. I changed the Hsync and Vrefresh for both drivers.
When you try the command Xorg -configure and then Xorg -config xorg.conf.new, I get a nicely configured screen, but when I copy the xorg.conf.new to /etc/xorg.conf, X will not startx. "illegal extended x86 opcode!" error appears. I searched in several sites and forums unsuccessfully for an answer to solve this kind of error.
As to " Adding monitor-related settings in xorg.conf will not replace a failing video card driver.", you are right.