Just how much can I fit into 4 Gb?

[yamanash]

Hey guys,
just wondering if anyone could give me a rough estimate of how big a scene I could hypothetically cram into 4 gb of vram.. I read a post over on another forum by a man claiming to have done a scene with a few 8k textures and about 8 million polys on a 4gb quadro 5800 without issue in octane. Is that feasible with 4gb or was he likely exaggerating? I am really trying to get a good idea of the limits of this method for rendering before I commit to buying some very pricy gpus (gtx680 4gb)

Thanks!

[t_3]

regarding the 680s, you should hold your horses as they are currently not working with octane. it needs to be updatet to make use of the appropriate new cuda build and most probably it will need some time for kepler ready apps to utilize the full power of the architecture as there were quite some changes.

regarding vram usage; will put some number together, as this was asked quite some times lately...

[yamanash]

Alright thanks,
it is much appreciated; and no I do not intend on putting this system together until everything is working properly, and as far as I know the 4gb version is not even available for purchase yet. I also want to see what Ivy bridge has to offer as far as overclock ability goes, since sandy was a pretty big let down in that regard.. I look forward greatly to seeing these numbers though!!

Thanks again!

[t_3]

I also want to see what Ivy bridge has to offer as far as overclock ability goes, since sandy was a pretty big let down in that regard..

*looks at his footer*

i can't say, that i'm really disappointed; won't dare for much more without going nitro

[yamanash]

Haha! Nice, though I was referring to the xeon family . If the memory situation proves to not be to big of an issue though, I see no need to go that route (nor would i want to with such poor ocability).

[pixelrush]

If you are pretty much just loading polys 4gb vram will hold about 20m tris max.
To get that into Octane you will need 24gb sys ram or maybe more.
I guess on average you might anticipate 13m tris with textures and film...depends....

[t_3]

some numbers:

• for 5mio resulting tris, octane needs around 800mb vram, ~2gb system ram, and additional ~2 to 8+(!) gigabytes of system ram while parsing and voxelizing (depending on the complexity of the scene)
• a 4096x4096 "image" map needs 64mb vram, and -apparently- ~2 times the original raw image size (~100mb for a rgb image);
• a 4096x4096 film (=output size) would need 320mb vram (20 byte per pixel) and the same amount of system ram

note: system ram usage not counted to the exact byte, only taken from the changes in the taskmanager...