Poor Video Refresh - Yuck!

[Woodshop Flunky]

I've got MAME running on an P3 with 512meg running XP.  I also have the same MAME setup running on a Core 2 Duo with 4gig running Windows 7.

I'm using a CRT VGA monitor rotated vertically.

The problem I'm noticing (on both setups) is that some games like Xevious and Twin Cobra seem to have a "shift" in the graphics that kind of scrolls across the screen.  It's kind of like looking at the monitor through the blades of a fan, but not nearly so pronounced.

Is this to do with the games originally being developed for 15Khz monitors, and I'm using a multi-scan monitor running at a higher resolution and scan rate?

Or is there some other issue.  I've only noticed it on scrolling games.

Any ideas?

Thanks!

[MonMotha]

This sounds like "tearing".  Check that you have vsync or triple buffering turned on in your emulator.

[lilshawn]

v-sync. nuff said.

:if nuff said=0 then

The artifact occurs when the video feed sent to the device isn't in sync with the display's refresh, be it due to non-matching refresh rates, or simply lack of sync between the two. During video motion, screen tearing creates a torn look as edges of objects (such as a wall or a tree) fail to line up.

During the vertical blanking interval, the driver would order the video card to either rapidly copy the off-screen graphics area into the active display area (double buffering), or treat both memory areas as displayable, and simply switch back and forth between them (page flipping).

[Woodshop Flunky]

Yep!  That fixed it.  Looks great now!  I set waitvsync=1 and left syncrefresh=0 in the config file.

Thanks a ton!