upgrading video card

[dot_bat]

greetings, i have a question concerning cores in the card. would it be better to have roughly a combined 3000 cores in one 4gig 680's and one 2gig 680 or would roughly 1500 cores in one 4 gig 770 be better? I'm on a mac and would have to have them flashed. i think i read octane would use all 3000 of them, no sli needed. would i have 6gigs of video ram in the 680's or 4 gigs ram? thanx for any help!
the specs are Mac Pro|OS10.10.3|2 x 3 GHz Quad-Core Intel Xeon|10 gigs ram NVIDIA Quadro 4000 2048 MB|

[rappet]

The OctaneBench give these performance results:
680: 53
770: 57
You can find it under 'Resources' on top of the forum.

So, two 680 will have a performance of 106 for scenes smaller then 2 gb.
Keep in mind that your 680 2gb will not render your scene is bigger then 2gB... Then still you have one 680.

Greetz,

[dot_bat]

thank you for reply rappet. i thought vram might be cumulative so i would need two 4gig cards to render anything larger than 2 gigs? I'm ignorant on this subject but would like to get a reasonably fast system going. thanx again rappet

[rappet]

thank you for reply rappet. i thought vram might be cumulative so i would need two 4gig cards to render anything larger than 2 gigs? I'm ignorant on this subject but would like to get a reasonably fast system going. thanx again rappet

You can render scenes bigger them 2gig, but then only the 4gig card will render and the 2gig will not.
When the scene is smaller then 2gig, both cards will render, so then you have double power.

When you need to render scenes larger then 4gig these cards won't be able to render,
and then you would need a card with more vram like 980 or Titan 6gb .
When need to render even larger scenes there is the The Titan x with 12 gb.

The scene size is not only determined by object volume (triangles), but also by textures and resolution.
Out of core textures is a way to reduce the loaded vram... also using efficiënt (not too large sized) textures can help in keeping the load low.

[dot_bat]

thanx again rappet for clearing that up for me. I'm on a old Mac Pro and am very limited in choice of cards and need to get flashed anything that nvidia doesn't provide for macs. makes sense to me know thanks for your help!

[cjadams]

That is why i'm looking into the Cubix external enclosures for video cards.

http://www.cubix.com/xpander-desktop

Now i just need to know how much Out of core is saving me... vs paying 2x as much for a titan x with 12gb.
vs. the 980 6gb