Anti-epilepsy filter?

[Sneaksie]

I'm sure that Luthier will clarify this, but as i understand the game uses a full-screen routine (shader i assume) that compares EACH pixel in two subsequent frames to make sure there are no sharp changes in brightness. If there are sharp changes (and almost all in the game has these sharp changes - dark planes on bright sky), this shader makes the brightness change more subtle to not to cause a stroboscope effect.
As you can see, this should increase load on GPU and potentially is uncompatible with SLI rendering (or make SLI slower than a single card) since you can't just render on two GPUs - you need to compare results of this rendering and then alter them.