Using MAME on an Arcade Monitor  
MAME and Monitors
Arcade Monitors
Saturn Mod
Arcade Primer
Finding a Cabinet
IC Pinouts
Using MAME's SVGA Arcade Monitor Mode

There are basically 2 reasons to use MAME's SVGA mode on your arcade monitor/TV
   640x480 'hires'
   16bit colour support

The SVGA drivers
As mentioned there are currently 2 SVGA drivers in MAME
   ATI and Generic

The ATI driver writes directly to custom hardware on the video card to generate the 640x480 mode
and will support any ATI card based on the Mach64 chipset with an internal dot clock
or... to put it another way -
(recent)Mach64, Rage Pro, 3D charger, Xpert@Play and Xpert@Work cards

The Generic driver writes to the standard VGA register set to generate the 640x480 mode
and may , or may not , work with a given chipset
  The ATI driver gives you 8 and 16bit colour support as well as an interlaced display
The Generic driver (if it works with your chipset) gives you 8 and 16bit colour support
but no interlaced display

Getting 16bit Colour on your Arcade Monitor
This crops up a lot, especially with reference to NeoGeo games -

You run a NeoGeo game in MAME (on your arcade monitor), but the colours are all wrong and the screen
seems 'stretched' horizontally

What's happened is this - the game requires 16bit colour, and MAME's 'depth' config item (colour depth)
is set to 16. So MAME runs the game in 16bit mode but you're running on an arcade monitor and you
haven't explicitly asked for an SVGA mode - so (for safety reasons) a normal VGA mode is used instead.
VGA is only 8bit, so the display appears 'stretched' and the colours are all wrong

This is purely to avoid damage to your arcade monitor - if the MAME SVGA drivers don't work with
your card it could end up sending a too high scanrate signal to your monitor

So there's 2 options -
   set 'depth' to be 8
   set the game to run at 640x480

The first option just means that the game will be forced to run in 256 colours
The second means you'll get 16bit colour support (if the MAME SVGA drivers work with your card)

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