Unfather: Just wanted to contribute my two cents. I'm very careful to edit my graphics settings for performance without exchanging much visual fidelity and this was the best route for me on a Toshiba Satellite C855-S5111 in Windows 8 (this also fixed the terrible graphic flickering and tearing I had initially):
- Go into Advanced Settings of Beyond Good & Evil Settings panel
- Check Manual compatibility settings
- UNcheck HW Vertex Processing
- UNcheck W buffer
That should fix the graphics problems as well as make the game playable. For the slowdown I experienced in heavily lit areas like the Main City and Slaughterhouse:
- UNcheck Multi Vertex Stream
For overall increased performance, lower the anti-aliasing slider.
NOTE: Those familiar with tweaking graphics settings know that typically there's a pretty big performance payoff for lowering general Water detail settings and Shadows quality. HOWEVER, I found that to be untrue for this game with my setup. Despite some pretty good reflection quality in the water, I received almost NO noticeable framerate increase from dropping these settings even to their LOW and OFF settings, respectively. Same with Flare, but that wasn't a surprise.
I unchecked HW Vertex Processing which fixed all the flickering graphics.
And by unchecking Multi Vertex Stream, this fixed the huge lag I suffered when I entered the city. Now I don't have to lower the water detail to fix the lag.