"Emulate async read" parameter

[sundance2]

just a minor follow up:

Now that I've got a better understanding of how SYNC/async works,
I got back to older titles featuring choppy in game animations,
and proceeded to reduce the async value parameter.
And sure enough, on reaching low enough values, the choppy effects disappears !
The effect was especially pronounced in DoA2.
Note that the game can run slower at times, but it remains smooth, which is miles better than previous choppiness.

Thanks @SWAT!