Stuttering and extreme drops in FPS in P3Dv4

[davetfc 4]

Hi

I'm a new user to P3Dv4 since half December 2018. Up till then I was using FS9 and FSX on a MSI Gaming laptop (GT62VR 7RE Dominator Pro – Core i7-7700HQ  processor with 4 cores and 8 LP, GTX 1070 GPU with 8GB). Since the installation of P3Dv4, I've been experiencing during my flights regular stuttering and sudden extreme drops in frame rates from the 30's FPS to 7 or 8 FPS. I tried dialling down all the settings, even playing around with the affinity mask setting. All this to no avail! 😥

After further extensive testing, I discovered that these drops in frame rates was somehow linked to the weather. On clear skies or days with good weather the sudden drops in frame rates and stuttering seem to be much less frequent, if not non existent! So I investigated further in that direction with Active Sky and found that when the weather was bad (rain or snow with poor visibility – for example less than 5000m) the stuttering and drops in frame rates were more pronounced and occurring every minute or so.

So did I find a solution to this problem? Yes! Hooray! 😄 In the weather settings in P3Dv4, I found an option 'Volumetric Fog' that was per default turned on. I decided to turn this option OFF. Since then the stuttering and sudden extreme drops in frame rates are gone. I can even dial my settings back up and fly around smoothly with frame rates between 20's and 30's.

I do not see much difference in the sceneries whilst flying after the change of this setting. My questions are therefore:

- What does the setting 'Volumetric Fog' do actually?
- Could there be an issue with this 'Volumetric Fog' setting in P3Dv4?

Can someone comment on this. Many thanks!

Kind regards

Dave
 

[vgbaron 3,496]

it was LM's attempt to create a reasonable fog/haze layer and eliminate the milk puddle effect around mountains. If you use AS you do not need VF enabled as the AS haze layer is more than adequate. As you found out, the combination of AS plus the VF enabled is rough on the system due to the way FSX/P3D handle AA.

I generally lock my fps at 20 and with no VF I can do Cat III approaches and never see the runway until I hit it.

Vic

[jabloomf1230 2,445]

Vic,

Is that mentioned somewhere on the HiFi forums? I always thought HiFi recommended VF to be on in the sim. Else, the FSX version of fog is depicted. Thanks.

Jay

[vgbaron 3,496]

With the stronger systems available now running both is a viable alternative Jay. I'll try to find the discussion but IIRC it was basically one or the other back when AS/P3D were first released. The best look, IMHO is both enabled but it can cause issues o weaker systems.

Vic

[jabloomf1230 2,445]

Ok thanks. I took a quick look at the HiFi forums in the meantime and I didn't see anything recent about it.

[davetfc 4]

13 hours ago, vgbaron said:

it was LM's attempt to create a reasonable fog/haze layer and eliminate the milk puddle effect around mountains. If you use AS you do not need VF enabled as the AS haze layer is more than adequate. As you found out, the combination of AS plus the VF enabled is rough on the system due to the way FSX/P3D handle AA.

I generally lock my fps at 20 and with no VF I can do Cat III approaches and never see the runway until I hit it.

Vic

Thanks for the information, Vic!