I came back to simming a few months ago after having built myself a new box (i7, Radeon HD4870 X2, 6GB RAM etc.). Soon after I discovered that the DX10 looked better (colors, bloom etc). Recently, I've been trying the "Adaptive Light Effect", but canned it after a few tests because I felt the performance loss wasn't worth it. I was never able to run that thing in full screen, which gives me better performance in DX10 mode, so I assumed the windowed mode along with the effect taxed my system too hard. Before I went back to DX10 I tested turning the effect off and went to full screen DX9 mode, just to see the difference in performance compared to DX9 windowed mode. I was surprised to see there was hardly any difference at all. I got more or less the same FPS as I did in Windowed mode with the adaptive light effect ON.In my tests I lined up at YSSY in fair weather and got aprox. 10 FPS in DX9, windowed mode as well as full screen, with or without the adaptive light effect (most sliders in the far right). I then switched back to DX10 mode, full screen and gained 5-6 FPS. Is DX10 that much better compared to DX9 or does it just run that much better on my hardware?Cheers/Jonas

I have the opposite result as you. I have an i7 with a GTX 285 1 GB RAM and 6 GB system RAM running 64 bit Vista OS. DX10 mode does not perform as well as DX9 for me. There is a larger discrepancy for me in windowed mode. DX10 works better in full screen as does DX9. Keep in mind that DX10 mode in FSX is not really DX10. It is a DX10 preview which simulates DX10. I didn't notice a big increase in quality with the DX10 preview so I keep it turned off and instead boosted my AA and AF settings as well as my screen resolution.

Keep in mind that DX10 mode in FSX is not really DX10. It is a DX10 preview which simulates DX10.

Not quite right (or better said: totally wrong :( ): it is 'real' DX10. You can't simulate DX10... They called it 'preview' because they could only implement very few DX10 options: a lot less than was promised. So the preview only shows a little bit of what DX10 can do... (and it even shows this in a bad way because DX10 in FSX got various disadvantages, like shimmering textures, no progressive taxi, no possibility to use the drivers or nHancer's superior FSAA and AF, etc.).Most people find DX10 runs better on their computer, but also most people return to DX9 because after a while the disadvantages become clear. For instance, fps is higher because FSAA is of a lower quality (you can only use the FSX FSAA). Only a few out here still use DX10. You could of course become one of them: it's all a matter of personal preference and probably indeed also has to do with hardware: on some computers it might accidently run better indeed... :(

On my rig in my signature below, DX10 does perform better in FSX. Though, with recent tweaks to the config and whatnot, that gap is much smaller now and in some cases DX9 outperforms DX10.

Adaptive light effect isn't meant to work with DX10, just with DX9.