ATI Adapters README file : XF86Config specifications : Clocks : Clocks for fixed clock generators on ATI adapters
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5.2.3. Clocks for fixed clock generators on ATI adapters

This section applies to all ATI adapters except all but the very earliest Mach64's.

One of the following clocks specifications (or an initial subset thereof) can be used depending on what the adapter uses to generate dot clocks:

Crystals (VGA Wonder V3 and V4 adapters only):

  Clocks  50.000  56.644   0.000  44.900  44.900  50.000   0.000  36.000
          25.000  28.322   0.000  22.450  22.450  25.000   0.000  18.000
          16.667  18.881   0.000  14.967  14.967  16.667   0.000  12.000
          12.500  14.161   0.000  11.225  11.225  12.500   0.000   9.000
ATI 18810 clock generator:

  Clocks  30.240  32.000  37.500  39.000  42.954  48.771   0.000  36.000
          40.000  56.644  75.000  65.000  50.350  56.640   0.000  44.900
          15.120  16.000  18.750  19.500  21.477  24.386   0.000  18.000
          20.000  28.322  37.500  32.500  25.175  28.320   0.000  22.450
          10.080  10.667  12.500  13.000  14.318  16.257   0.000  12.000
          13.333  18.881  25.000  21.667  16.783  18.880   0.000  14.967
           7.560   8.000   9.375   9.750  10.739  12.193   0.000   9.000
          10.000  14.161  18.750  16.250  12.586  14.160   0.000  11.225
ATI 18811-0 and ATI 18812-0 clock generators:

  Clocks  30.240  32.000 110.000  80.000  42.954  48.771  92.400  36.000
          39.910  44.900  75.000  65.000  50.350  56.640   0.000  44.900
          15.120  16.000  55.000  40.000  21.477  24.386  46.200  18.000
          19.955  22.450  37.500  32.500  25.175  28.320   0.000  22.450
          10.080  10.667  36.667  26.667  14.318  16.257  30.800  12.000
          13.303  14.967  25.000  21.667  16.783  18.880   0.000  14.967
           7.560   8.000  27.500  20.000  10.739  12.193  23.100   9.000
           9.978  11.225  18.750  16.250  12.588  14.160   0.000  11.225
ATI 18811-1 and ATI 18811-2 clock generators:

  Clocks 135.000  32.000 110.000  80.000 100.000 126.000  92.400  36.000
          39.910  44.900  75.000  65.000  50.350  56.640   0.000  44.900
          67.500  16.000  55.000  40.000  50.000  63.000  46.200  18.000
          19.955  22.450  37.500  32.500  25.175  28.320   0.000  22.450
          45.000  10.667  36.667  26.667  33.333  42.000  30.800  12.000
          13.303  14.967  25.000  21.667  16.783  18.880   0.000  14.967
          33.750   8.000  27.500  20.000  25.000  31.500  23.100   9.000
           9.978  11.225  18.750  16.250  12.588  14.160   0.000  11.225
ICS 2494-AM clock generators (found on some Dell motherboards):

  Clocks  75.000  77.500  80.000  90.000  25.175  28.322  31.500  36.000
         100.000 110.000 126.000 135.000  40.000  44.900  50.000  65.000
          37.500  38.750  40.000  45.000  12.588  14.161  15.750  18.000
          50.000  55.000  63.000  67.500  20.000  22.450  25.000  32.500
          25.000  25.833  26.667  30.000   8.392   9.441  10.500  12.000
          33.333  36.667  42.000  45.000  13.333  14.767  16.667  21.667
          18.750  19.375  20.000  22.500   6.294   7.081   7.875   9.000
          25.000  27.500  31.500  33.750  10.000  11.225  12.500  16.250
VGAWonder VLB, VGA 1024 VLB, Mach32 and Mach64 owners should only specify up to the first 32 frequencies.

Other clock generators that have been used on ATI adapters (which can all be said to be clones of one of the above) might generate non-zero frequencies for those that are zero above, or vice-versa.

The order of the clocks *is* very important, although the driver will reorder the clocks if it deems it appropriate to do so. Mach32 and Mach64 owners should note that this order is different than what they would use for the accelerated servers.


ATI Adapters README file : XF86Config specifications : Clocks : Clocks for fixed clock generators on ATI adapters
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Next: Clocks for non-ATI adapters