Where is one more GB ?

[R_Flash]

Hi. I have two videocards in my comp (780Ti 3Gb and GTX 980 4Gb). But Cinema 4D recognizes all 4Gb only then 780Ti card is off and excluded from render process . When I turn on both cards in GPU Info toolbar I see only 3 Gb videomemory. Why?
Thanks.
Regards.

[aoktar]

It's not a matter that how much ram is recognised. Octane can use the vram as minimum amount of. It hold same data in each gpus to work parallel.

[R_Flash]

So if I want render with both videocards I can use only 3Gb vram?

[aoktar]

So if I want render with both videocards I can use only 3Gb vram?

yes, that's a simple logic.

[R_Flash]

...but very sad!

[aoktar]

You forget that first card will loose some extra vram due OS's and C4D's needs. Practically it's impossible to have free 4Gb on first gpu .

[R_Flash]

Aoktar, no of course I did not forget about it. I know that Otane dose not add vram of installed cards. But why I can`t use GTX 980 memory for Octane render and 780 Ti for OS`s and C4D? And use power of cores both cards for render? Why I need turn off one of videocards for using maximum memory?
Sorry, if my questions seem silly to you

[aoktar]

It's not a matter that how much ram is recognised. Octane can use the vram as minimum amount of. It hold same data in each gpus to work parallel.

This should be clear to explain. It has to copy same data to each gpus. How can you copy 4gb data to a gpu which has 3Gb?

[R_Flash]

It's not a matter that how much ram is recognised. Octane can use the vram as minimum amount of. It hold same data in each gpus to work parallel.

This should be clear to explain. It has to copy same data to each gpus. How can you copy 4gb data to a gpu which has 3Gb?

Ok, I understood. Thanks a lot for the clarifications.