First I thought it was my addon scenery causing significant drop in framerates until I realized that it was only from inside the VC cockpit I have the problem.
In FSX there is a facility to check if you want "High-resolution 3-D virtual cockpit", or not, which I always deselect with brilliant textures anyway and acceptable framerates. In P3D4 there isn't any facility like that. 
Any suggestions to get around this? 

Hi Phillip

What are your Hardware Specifications? what are your Anti Aliasing Settings? if you're running on SSAA, try using MSAA 4x (and if you have an NVIDIA graphic card set it in your NVIDIA Inspector too. 

 

Please also check this thread:

 

Greets,

Marc

Hi.

Dynamic lights can induce severe fps drops when you are at an airport scenery that was not converted for P3D v4 even VC. This doesn't happen at stock airports or sceneries correctly converted. Try unchecking the dynamic lights in the lighting settibg when this happens.

Thank you guys, but I've been through all that and also read the nice PMDG article...+ more
Besides my Anti Aliasing settings are the lowest possible. I'm using AMD/Eyefinity - NOT Nvidia, as it doesn't support my kind of multi-monitor setup.

As I wrote, the problem wasn't present in FSX - now it is, probably because it's not possible in P3D4 to choose a panel state with lower resolution.   

As far as I can tell on my side going from the same hardware from FSX to P3Dv4 there is a huge difference in the good way, even on big sceneries I'm nowhere really far below 30fps, while before I'd easily get to the 15 fps line.

If you have an older hardware it might explain the drop because the graphical engine is more recent and there is a lot more that is done, like cockpit shadows which makes a big difference, the HDR might also put quite more stress on the GPU. While both sims are still CPU limited, I really think the GPU is really much more used by P3Dv4.

17 minutes ago, wedgantilles said:

 While both sims are still CPU limited, I really think the GPU is really much more used by P3Dv4.

You might have an important point right there!

My GPU's are actually quite new. But with FSX being so particular processor oriented I use to ignore GPU overclocking - BUT with P3D4 it seems to be another thing.
I think I'll try and kick that GPU a bit and see what happens..

PS. CPU is running 4.2 ghz

It's always a good idea to post your system specs at the bottom of the page as part of your signature.

It saves the mods a lot of work.

 

17 hours ago, slimfly said:

My GPU's are actually quite new.

Well quite new does not mean a lot can you tell us hat GPU you're using. 

On my side for example I have a GTX 1080 so I did not tweak a single thing. You should also check what you're using as far as antialiasing used by Prepar3D depending on the resolution you use as well. Because I don't think you can get quite a huge improvement by overclocking a GPU which is not as simple as it is for CPU. Also the gain from a version to another often is not as much the speed than the number of computing modules and so on.

Problem solved!!

I simply changed the MAX_VC_TEXTURE_RESOLUTION= from 1024 to 800 inside the cfg.
and now got all my FPS back inside the cockpit, as I'm use to in FSX  - still with brilliant texture quality as I'm use to in FSX!

You tend to forget that I have no problems whatsoever with FPS outside the cockpit almost regardless of my GPU, SSAA and MSAA settings. My problem was entirely from inside the cockpit.

Anyway, my GPU system:
2 x AMD Radeon R7 370, 4GB serving 8 monitors - 6 of the monitors are joint together via Eyefinity to one 3840x2048 resolution big screen. The other 2 monitors - each res. 1280x1024 are for the overhead panel and the flight desk.
A quite demanding system which I during the years actually have managed successfully to tame over all - Just had this little obstacle with the P3D4, within the GUI, not being able to choose between moderate and HD panel resolution, which is an option inside the FSX GUI.