Hi Kaphias, I am getting variable results; I have got vv high frame rates, and a reasonably clear picture, but this was flying ove bare featureless terrain ( ELGC tp LFAT). Frame rates drop & vary, and the fog comes down once I get to any thing with features, ( over Paris, incredible scenery, or at LFPG) My frame rates have varied from 22 to 128!! Frankly I am not too conerned with frames rates, the motion always seems fluid and convincing, its the limted visibility and fog which is worrying; also the fact that it does not seem possible to use clouds without affecting performsnce. Surely my set-up should run this sim without so many rendering limitations. I have taken a screen shot of the rendering page. How do I get it to you? Many thanks for your inerest and help. Lusitano.