Hi,

 

Had FSX since release, but due to CTDs I pretty much never flew it until recently.

 

I found out by accident the other night, that regardless of the cloud type, if I zoom in on the clouds (yes, zoom IN), the FPS drops like a rock until it is in single digits (2-3 FPS).

 

Why do the clouds have such a negative impact on frame rate, and does anyone know of a way to increase the perf? Ironically, zooming OUT improved the frame rates.

 

I have always noticed that the sim stutters/slows with lots of clouds (and cloud layers are particularly problematic).

 

Note that I'm only using the stock clouds, and the texture res is limited to 1024x1024.

 

I thought it very interesting that perf dropped dramatically when zooming in on clouds (zooming into clear skies or the ground don't affect FPS).

 

Best regards,

Robin.

Real-time rendering of a volumetric 3D shape is highly processor- and memory-intensive. Most skies in 3D games are postage stamps pasted onto a surface; not FSX.

 

 

I don´t have many problems with clouds, I guess it depends a lot on your PC and your AA settings etc, but you didn´t give us a clue about either of those.

I guess I need a faster graphics card.

 

I don´t have many problems with clouds, I guess it depends a lot on your PC and your AA settings etc, but you didn´t give us a clue about either of those.

 

AA is set to 8x, MSAA (the lowest without turning it off). AA is *OFF* in FSX, forced in the driver.

 

Card is 1Gb ATI AMD 6750.

 

Perf zoomed out is fine 40+ FPS. It was an interesting discovery that the clouds made such an impact in that way. Negative performance as the result of restricting the field of view is not normal in any 3D application. It should reduce the processing load, not increase it.

 

Best regards,

Robin.

Does it only happen when actually zooming in or do you also see a fps drop when just flying closer or through the clouds?

Real-time rendering of a volumetric 3D shape is highly processor- and memory-intensive. Most skies in 3D games are postage stamps pasted onto a surface; not FSX.

 

Well, in fact they are... FSX clouds aren't volumetric 3D.

Ah okay! I'm even more impressed by REX's cloud texture packs, then. Fooled me!

What about your cloud draw distance and cloud detail. Maybe try a 1024 DXT3 cloud.

The reason zooming in on the clouds kills performance is because it's gobbling up all your graphics card's "fill rate" performance. I won't go into the tech babble here but you can google to find out more.

 

Try disabling the FSX profile in your ATI tools and only enable AA in the FSX options, then try your zoom test again and see what happens.

Card is 1Gb ATI AMD 6750.

 

It's been noted through the years by many people like NIckN, Word Not Allowed, and many others that those cards dont handle clouds as well as Nvidia cards do. Not sure if that is still the case and am not familiar with that card, but the general consensus has always been to go with Nvidia cards for FSX use, especially for the problems that generate concerning cloud rendering performance.

 

On a side note, in 5+ years using FSX and having used a Nvidia 8800GTS 512, GTS 250 1GB and now a GTX 670 2GB, I have never experience an FPS drop when in heavy cloud cover, either zooming in on them or using a normal range zoom level using the normally recommended AA settings.The only thing that can effect FPS for me in a heavy cloud scenario is using cloud draw distances greater than 100 miles.

 

POST EDIT

 

Google "ATI cards and clouds in FSX" and you will get many hits talking about how bad ATI cards perform with clouds in FSX.

Try letting FSX set AA and turning off driver customizations.

 

Seriously, I've tried the Nvidia Inspector tweaks for instance and my system at least (680 GTX 2GB card) is much happier just running with the Nvidia defaults for FSX in the standard Nvidia control panel.

 

 

 

Seriously, I've tried the Nvidia Inspector tweaks for instance and my system at least (680 GTX 2GB card) is much happier just running with the Nvidia defaults for FSX in the standard Nvidia control panel.

 

I am sure your system is happier but are your eyes happier too...?  ^_^ I use Word Not Allowed's settings and with those I hardly see any shimmering and ragged edges. When I use lower settings (and certainly when I use FSX defaults) all the lines in the VC of my Lanciar Legacy move all the time... really awful.

If you have an ATI card then you need to use the Shader 3.0 patch by Bojote. That'll fix it some what.

If you have an ATI card then you need to use the Shader 3.0 patch by Bojote. That'll fix it some what.

+1

I am sure your system is happier but are your eyes happier too...?  ^_^ I use Word Not Allowed's settings and with those I hardly see any shimmering and ragged edges. When I use lower settings (and certainly when I use FSX defaults) all the lines in the VC of my Lanciar Legacy move all the time... really awful.

+1