Do NOT run benchmarks in compare mode when screenres is too low

[Kano]

There is a good example why this should not be done:

http://global.phoronix-test-suite.com/?k=profile&u=darthanubis-24080-1886-9887

The first test was run with 1920x1200, then compared against a system with 1440x900.

Lots of games would use 1440x900 then, vdrift is more extreme and resets all settings and uses the defaults which will lead to a small window running the game. Over 300 fps is the result with a lowend gfx card then...

So do not even attempt to run 3d benchmarks when the screenres is lower than the first test.