Amnesia startup stuttering/Lag on my Ati HD4850

[Thomas]

Try to set every setting to the lowest setting possible and see if it still stutters (make sure to turn off all post effects in game in options->graphics). Also make sure to turn down the resolution as far as it goes.

If this removes the problem, turn on every feature one by one and see if the stuttering returns.

If the problem is still there, update drivers as described in troubleshooting guide (A.1) and make sure there is not app running in the background (skype, firefox, anti-virus, etc)