If you have a RAMDAC that is not listed here, be VERY careful not to overdrive it using XF86_S3. Better contact the XFree86 team first to verify that running XF86_S3 will not damage your board.
If you feel adventurous you could also open up your computer and have a peek at your RAMDAC. The RAMDAC is usually one the larger chips (second or third largest chip that is NOT an EPROM) on the board. The markings on it are usually
<Company logo>
<company identifier><part number>-<speed grade>
<manufacturing week><manufacturing year>
<lot number><other funny numbers>
For example:
@@
@@ AT&T
ATT20C490-11
9339S ES
9869874
This is a AT&T 490 with a speed grade of 110 MHz. This would then mean
that you put a `DacSpeed 110' line in your XF86Config file. Be
advised that some RAMDACs have different modes that have different
limits. The manufacturer will always mark the chip naming the higher
limits, so you should be careful. The S3 server knows how to handle
the limits for most of the RAMDACs it supports providing the DacSpeed
is specified correctly.
chips labeled -80 or -8 should use `DacSpeed 80' in
the device section
S3716-ME SDAC ==> DacSpeed 110
SC15025-8 ==> DacSpeed 80
ATT20C490-80 ==> DacSpeed 80
Some RAMDACs (like the Ti3025) require some mode timing consideration for their hardware cursor to work correctly. The Ti3025 requires that the mode have a back porch of at least 80 pixel-clock cycles. A symptom of this not being correct is the HW cursor being chopped off when positioned close to the right edge of the screen.
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