MigrationHeuristic is a parameter for EXA to know when to "migrate" pixmaps to video memory. Possible values are "always", "greedy", and "smart". It can be applied by adding a specific line to the divice section of your xorg.conf. For example:

Section Device
    ...
    Option "MigrationHeuristic" "greedy"
    ...
EndSection

Currently the default is "always" ("smart" on older xorg).

(jwstolk, xorg 1.4.0.90, NV15, 2008-01-28: rendering a scaled image in firefox took +/- 60 seconds. switching from always to greedy fixed this.)

For best performance, use: