Question 32-bit App Address Space on 64-bit OS/GPU Size?

Jan 17, 2020
Hello all, I've been putting this post/question off for some years now. However the question has been raised.
A 32-bit process on a 64-bit OS, is limited to 4-Gb Address Space. I would like to ask the follow questions.

A number of posts on the web state, 32-bit windows OS, the graphics memory, bios are included in the 4gb Address space = 2.75gb available.
I've done research about 32-bit OS and how v-ram was shadowed in VAS, 1-gb GPU = 2-gb video ram and 2-gb system ram. DirectX 9.0c (and below).
There was a patch for 32-bit apps, 3gb system ram and 1gb video ram usage and not needed in later OS releases as shadowed v-ram was addressed if that is the case.

However I am curious, under a 64 bit OS running such 32 bit games (old or new). Does GPU size (2/4/8-gb cards) affect the Address Space in windows 10? or is it split 2-gb system ram, 2-gb video ram ect. And the 4gb Address Space is not affected by what size GPU (depending on gpu specs) + Windows 10 64 bit OS the user has?

I have done a lot of reading and built games in both Dx9 and Dx11 platforms, however if using a 32-bit game engine,
would having a lower GPU size add less demand on the 32-bit game Address Space and prevent crashes, based on a game using more System Ram usage and using less demanding graphic details?
From research and Test games, most users with a 4gb GPU seem to encounter crashes or stalls, unlike a user with a lower GPU not experiencing those problems (personal research, polls and tests).

Or is it advised to create smaller/less demanding games in a 32-bit App environment all round, that sit under the 4gb Address Space usage. Such as lower texture sizes, if the case that Gpu size (example a 4-gb card) does limit 32-bit app System Ram in the Address Space on Win 10 64-bit OS?
Due to reported issues and crashes with 32-bit games in Win 7, 8 on the net, and most replies suggest the end user to reduce the Graphics settings to lower less demanding settings or upgrade GPU/Ram?

Questions are based on varied System Ram usage & Video Ram (Gpu) depending on game data of course,
However my main query is, when playing a 32-bit Game on Windows 10 with different size GPU.

if the end user had a 2gb GPU and usage was at 100%, this leaves around 2gb System Ram?

In the case of using a 4gb GPU and usage was at 75% (example: higher texture size), would this balance at 1Gb of System Ram available?

Example for the following question,

Win 7 64bit OS+ 2gb Gpu, running a 32-bit Game (made in Win 7 / Dx9.0c or below) = Address Space break down?
Win 10 64bit OS+ 2gb Gpu, running a 32-bit Game (made in Win 7 / Dx9.0c or below) =
Win 10 64bit OS+ 2gb Gpu, running a 32-bit Game (made in Win 10/Dx9.0c or below) =

Win 10 64bit OS+ 2gb Gpu, running a 32-bit Game (made in Win10/Dxx11) =
Win 10 64bit OS+ 4gb Gpu, running a 32-bit Game (made in Win10/Dx11) =

Thank you all very much for your time. Looking for the big hitters out there as I have read many mixed replies on this topic.
I have asked this question to Microsoft, though trying to get a broader opinion on the topic and always heard this is the place the experts drop by. Thanks again.
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