Just picked this up on the PMDG forum. Take a look at any of your aircraft from the outside. Turn off the lights and turn on the lights. Look at your frame rates. Bet they are about 25% lower with the lights on.Sounds like a good job for those of us who can do some programming. Not me as you would not want to see the result. JohnBAW317CaptainToday flying the PMDG 1900 D and the IFDG Airbus 320.

This may not be true in all cases John. I just tried it with the default RealAir SF.260, the default PMDG 736, and the default Cessna and see no change in the framerate for any of them. These things always seem to be more complex than they first appear. Did the poster at the PMDG forum give a clue as to the hardware used?DougNorthwood 2.2a at 2.72Ghz (Intel HSF)Abit TH7II-R512MB Samsung 40ns PC800Radeon 9800 Pro (128MB)Cat. 4.2's DX9b WinXP Pro5 WD HDD's (20GB, 60GB, 120GB, 120GB, 120GB)Plextor 708ASony DDU-1621Inwin case / Enermax 431W PSU

Go to Options, Settings, Display-Hardware Rendered Lights. If the slider isn't to the left, set it that way and test fps again. When this option is maxed, it can cause turning on the lights to hit fps a bit in some aircraft...-John

Just a cautionary note here: Depending on the power of your system and the type of video card, some aircraft lighting requires hardware lighting effects to be enabled in FS9. Again, depending on the type and power of your set up, most users will see no perceivable drop in performance at all with all lighting effects on. Others will see a small drop in frame rates but this is rare.In systems where performance is affected, I would guess that there are other sliders to reduce more efficiently (eg: clouds and scenery) before lighting economies are tried.Kind Regards,Rob Young - www.realairsimulations.com

Which lights are you refering to? Beacons and strobes, landing and taxi, all? I can't say that I've noticed a fps hit before, but if your video card can't handle DX9 I would think that perhaps those beacons and strobes may affect performance and they appear to be using one of the shader technologies...possibly better handled by a DX9 capable card. I have a Radeon 9700 and it has no problems with that! Not being a programmer I have no idea what techniques are used, but I could see that overall, on any system, maybe landing and taxi lights may cause a performance drop, but again, I've not noticed a problem....

I'm referring to lighting effects in my response. If the H/W lights slider is left, you'll still get landing lights, etc.... As you move it to the right, you get some nice effects, such as the strobes flashing off of the wings, interior lighting glow, and even strobes flashing off of the interior walls.It may well be a card issue--the H/W lights could cause a hit even in FS2002, which did not use DX-9. But since I upgraded to a GEF-4200, I can't really detect a fps hit in either sim. And flying at night with that strobe effect sure is immersive...Anyway, in a nutshell the slider doesn't control the lights, but the effects surrounding them...-John