VideoMemorySizeMb 4064 or 4096

[kesss]

My card is gtx970. For "VideoMemorySizeMb" parameter I used VRamSizeTest tool which showed me 4064 MB. But shouldn't it be 4096? What the difference at all, could you please explain?
And which of numbers better to enter up for the parameter?

Btw, If I run VRamSizeDX11.exe it shows me 44064 MB. How could it be such a huge amount of VRAM?

Upd: win10 dxdiag shows 4059 MB, I'm confused

[ENBSeries]

Dx9 for dx9 games, Dx11 for dx11 games, obviosly. So if you trying to use it for old Skyrim, then dx9 test is valid only. Size 4064 is because i do not check size reported by drivers, but measure it by creating surfaces in memory and their size is relatively big and there is no point to measure precisely anyway, memory used by OS, browsers, drivers and other applications anyway, you can't just give entire to one game.
Dx11 can give huge reports because video memory in dx11 is shared, vram+ram+swap file max size.
Which value to set depends from software you running, but gf970 have issues with 3.5+ gb, so i think 3500 is okay.

[kesss]

Ok, got it.
Yeah, that 3.5 gb trick on gtx970, thought about it too.
As for 4064 or 4096, I also was wondering does it matter in general to choose and set a strict number of these two to avoid any issues? Or for example, if to set to 3495 or 3505 instead of 3500, will it cause any differences? What about 1024 GB x 3.5 = 3584 GB ?

My questions may sound silly, but I'm just a bit paranoid about random CTDs or FPS dropping So I'm trying to set my enblocal.ini ideally

[ENBSeries]

Precise values doesn't matter, because other software, OS do consume video memory and you don't know how many. After all, even if you set there small value, like 500, you will not get any more or less CTD, only performance will be worse with stuttering. But if value is too big, then driver may crash, other applications, the game itself, if reach the limit of course.

[kesss]

Ok, I got it. Thank you for your time and for ENB generally