The 4x the performance I mention is contrasting two games like the crysis engine and the unreal engine. Its not exact figures and I am aware they are totally different engines etc but what I am saying is, performance wise opengl will always top out king. The texture mapping I also mentioned is just to say that textures in opengl when rendered IMO look better than that of a directx texture. doom3 / quake4 for example... great coding team behind them, and I love the way the lighting and bump mapping throughout the game sets the scene perfectly and still has a decent frame rate. Ive been running linux for the last 7 years, occasionally popping back to windows to check how bad things are going, after trying the crysis game out I laughed and went straight back. Im anti microsoft and am fully aware of the microsoft conspiracy so im bound to say opengl > dx thats my personal opinion, im not brainwashed into thinking I need a new graphics card every month in order to play "DIRECTX 10 IN ALL ITS LEETNESS!" although I will still continue to code with the directx api as its industry standard. I cant really change that but if I can open other people minds up to the better alternatives out there I might possibly be able to make a difference...
Peace