I currently have a 1GB GeForce GTX 560Ti graphics card, and I have noted all of the comments about P3D requiring at least 2GB VRAM to run properly. However, I am curious to know if a 1GB card would be OK if I decided to run P3D with all external shadows disabled (in other words, like FSX). Is it the shadows that require all of that VRAM, or something else?

I have P3D V2 and my GPU is also 1GB (AMD though). I don't run P3D very regularly yet, but I have been able to get acceptable frame rates even with external and internal shadows turned on. I do get stutters though, which i think are supposed to be at least partially addressed in the next patch. Some people reported that tinkering with the processor affinity mask can improve the stutters, but I have not tried it yet.

 

If I have shadows turned off, I get frame rates very close or even higher than FSX, but for me one of the reasons to switch to P3D would be the internal shadows, which substantially improve immersion.

 

I know this does not completely answer your questions. maybe others can give more...

If you were to keep autogen levels in check and aren't too concerned with high levels of SSAA then sure, should be fine.

 

There is a common error made when looking at VRAM usage in DX11 applications, that what you see allocated is what is actually required for smooth operation. Many/most DX11 titles will happily allocate quite a bit more VRAM than is actually required. It is somewhat similar to RAM caching in windows...though technically unrelated, of course.

 

1GB isn't going to leave you much room for bells and whistles, but you should absolutely be able to achieve higher IQ than FSX without issue.

Look at this thread. http://forum.avsim.net/topic/427363-512mb-gt640m-will-work-on-p3d-v2-anybody-can-help-to-comment/

Spirit