VBEHzCFG
========


For the default settings you need a monitor with at least 82 kHz horizontal
scan frequency.



The RefreshRate field:
----------------------
Some BIOSes do not use the RefreshRate field set in VBEHz, they calculate
their own refresh rates:

                         Pixel clock
RefreshRate = ---------------------------------
              Horizontal_total * Vertical_total



Maximum refresh rates for the modes in VBEHz:
(I suggest to use 3-5 Hz less)

+-----------------------------------------------------------------------+
|max horiz. freq.| max refresh rate (non-interlaced) of your monitor    |
|of you monitor  | 640x480 | 800x600 | 1024x768 | 1280x1024 | 1600x1200 |
+----------------+---------+---------+----------+-----------+-----------+
|    30 kHz      |   58 Hz |   46 Hz |    36 Hz |     27 Hz |     23 Hz |
|    35 kHz      |   67 Hz |   54 Hz |    42 Hz |     32 Hz |     27 Hz |
|    40 kHz      |   77 Hz |   62 Hz |    48 Hz |     37 Hz |     31 Hz |
|    45 kHz      |   87 Hz |   70 Hz |    54 Hz |     41 Hz |     35 Hz |
|    50 kHz      |   97 Hz |   78 Hz |    60 Hz |     46 Hz |     39 Hz |
|    55 kHz      |  106 Hz |   85 Hz |    67 Hz |     51 Hz |     43 Hz |
|    60 kHz      |  116 Hz |   93 Hz |    73 Hz |     55 Hz |     47 Hz |
|    65 kHz      |  126 Hz |  101 Hz |    79 Hz |     60 Hz |     51 Hz |
|    70 kHz      |  136 Hz |  119 Hz |    85 Hz |     65 Hz |     55 Hz |
|    75 kHz      |  145 Hz |  117 Hz |    91 Hz |     69 Hz |     59 Hz |
|    80 kHz      |  155 Hz |  125 Hz |    97 Hz |     74 Hz |     63 Hz |
|    85 kHz      |  165 Hz |  133 Hz |   103 Hz |     79 Hz |     67 Hz |
|    90 kHz      |  175 Hz |  141 Hz |   110 Hz |     83 Hz |     71 Hz |
|    95 kHz      |  185 Hz |  148 Hz |   116 Hz |     88 Hz |     75 Hz |
|   100 kHz      |  194 Hz |  156 Hz |   122 Hz |     93 Hz |     80 Hz |
|   105 kHz      |  204 Hz |  164 Hz |   128 Hz |     97 Hz |     84 Hz |
|   110 kHz      |  214 Hz |  172 Hz |   134 Hz |    102 Hz |     88 Hz |
|   115 kHz      |  224 Hz |  180 Hz |   140 Hz |    107 Hz |     92 Hz |
|   120 kHz      |  233 Hz |  188 Hz |   146 Hz |    112 Hz |     96 Hz |
|   125 kHz      |  243 Hz |  196 Hz |   153 Hz |    116 Hz |    100 Hz |
|   130 kHz      |  253 Hz |  203 Hz |   159 Hz |    121 Hz |    104 Hz |
+----------------+---------+---------+----------+-----------+-----------+
|max horiz. freq.| max refresh rate (non-interlaced) of your monitor    |
|of you monitor  | 320x240 | 512x384 |                                  |
+----------------+---------+---------+----------------------------------+
|    30 kHz      |   58 Hz |   73 Hz |
|    35 kHz      |   68 Hz |   85 Hz |
|    40 kHz      |   78 Hz |   97 Hz |
|    45 kHz      |   88 Hz |  110 Hz |
|    50 kHz      |   98 Hz |  122 Hz |
|    55 kHz      |  108 Hz |  134 Hz |
|    60 kHz      |  118 Hz |  146 Hz |
|    65 kHz      |  127 Hz |  159 Hz |
|    70 kHz      |  137 Hz |  171 Hz |
|    75 kHz      |  147 Hz |  183 Hz |
|    80 kHz      |  157 Hz |  196 Hz |
|    85 kHz      |  167 Hz |  208 Hz |
|    90 kHz      |  177 Hz |  220 Hz |
|    95 kHz      |  187 Hz |  232 Hz |
|   100 kHz      |  197 Hz |  245 Hz |
|   105 kHz      |  207 Hz |  257 Hz |
|   110 kHz      |  216 Hz |  269 Hz |
|   115 kHz      |  226 Hz |  282 Hz |
|   120 kHz      |  236 Hz |  294 Hz |
|   125 kHz      |  246 Hz |  306 Hz |
|   130 kHz      |  256 Hz |  318 Hz |
+----------------+---------+---------+

These values are only for the pre-defined sizes, if you change
horizontal_total you have to calculate your own values:

                   max_horiz_scan_rate_of_the_monitor
max_refresh_rate = ----------------------------------
                            vertical_total



Notes:
 - The refresh max refresh rate may also be limited by the RAMDAC on your
   video board. In this case the BIOS will use the highest possible
   pixelclock which is lower then the one requestet by VBEHz.
 - Most monitors do not support hiher refresh rates than 150 Hz.
 - Too high refresh rates will limit the performance of your video card,
   with a NVIDIA RIVA 128 this happens at about 142 Hz.



The Flag field:
-----------------
Bit 0: Double Scan Mode    (1=enabled)	This has to be set if the vertical
					resolution is 300 pixels or less
Bit 1: Interlaced          (1=enabled)
Bit 2: Horiz sync polarity (1=negative)
Bit 3: Vert sync polarity  (1=negative)

However, you cannot enter bits, you have to enter integers:

input_value = (Bit 0) + 2*(Bit 1) + 4*(Bit 2) + 8*(Bit 3)






To activate the changes you made, you have to reload VBEHz, which can
only be done by rebooting.
(Or closing the DOS-Box under Win 9x if you didn't load VBEHz in your
AUTOEXEC.BAT file)

