Lost with gpu need's for Iray
tiamat
Posts: 21
Hello,
i'v read lot of thread here, but finally i dont found some answers. Wich GPU is needed for a " resonable " render time for a huge scene (without falling in cpu rendering) i mean, 3 or 4 genesis caracters and an environnement for exemple, without using scene optimizer.
It seems that the 1080, 1070 with 11 GB or 8 GB of VRAM are good investment, in contrary to the rtx 2080, because Iray doesn't use ray tracing techno.
I don't wan't to talk about pricing, but only hardware configuration who are working with iray. let's imagine you're favorite configuration for using Iray rendering 
!
Thanks in advance
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We don't yet know what impact it wil have, but it does appear that iray is going to support then new features of the RTX cards. It can already use them in the 4.11.x.x Public build, and they are reported to be substantialy faster than the 10x0 cards. However, the 10x0 cards are certainly still highly capable in their own right if you can get one at a reasonable price.
If I had the money, I would buy a RTX 2060!
The 2070 has 2 more Gb of VRAM.
Tanks for replying,
So the futur seems to be RTX techno and finally (always without talking about prices
), 20xx gpu generation will become a standard. but what about the RAM needed. i've read somewhere the most your scene is big, the most you need RAM also ? is it True ?
Yes, more items in your scene means more geometry and more textures maps to put in memory, so you need more RAM.
Yes, but VRAM is more important!
You can always buy more RAM.
For example, my motherboard has 4 RAM slot (the only downside of using 4 sticks instead of 2 is that your PC will boot 1 second later, but you don't want to use 3 sticks, because that way you'll revert to single channel). (Oh, and if you want to overclock them you won't be able to reach the same clock speed. For example when I had 2 sticks I was using them at 3000Mhz, from the default 2400Mhz, while now I can't go past 2666Mhz).
I started with 8Gb of RAM, and while rendering around 7Gb were occupied.
Then I bought 2 more RAM sticks, going to 16Gb of RAM, and now it usually occupies 12Gb. But I've not seen a huge speed improvement.
While if you run out of VRAM, you simply can't render with your GPU (and it will be much slower).
3 or 4 characters + environment is definitely within 2070 territory. It should be possible with 1080 actually and maybe even 1070 Ti. 970 will struggle. I would say as a general rule of thumb, starting at 4Gb for 2 characters + environment and add 1Gb for every additional character. The variable here is scene complexity (environment). The only reason I would prefer the 20xx series is the possibility of a future iRay update that makes use of the RT cores. That's if you aren't a baller and don't have money to burn.
Get as much vram as you can afford, it's the main deciding factor on wether you render with gpu or cpu. A few genesis 8 figures with level 4 subd is no problem(only really needed for like portrait type renders), but all their 4k textures could be a problem, unless you got scene optimizer, or feel like downsizing texture sets yourself when needed.
Hmm...always when I see these discussion I think conspiracy
Very happy to be a 3DL user, will always use the CPU for rendering, I have 8GB RAM in my IMac, no problems whatsoever to fit 20+ Genesis 1 characters with 4k textures, fully dressed and with hairs into my scenes. Bought the scene optimizer when it was on sale, never had to use it
What is reasonable?
If money no object (or you have the cash and have decided the cost is worth it); a 20 series: Titan would probably be best; failing that a 2080ti, 2080 will give 'reasonable', or as close as currently possible.
Aim for the current generation; 20 series, or failing that the 10 series (last gen).
Within a generation, compare CUDA cores and get as much RAM as possible.
Used to have 16GB ram with a 8gbVRAM (GTX1070). The 16GB for many characters in a scene was not enough. Render bogged. Used Sceneoptimizer and I was good again.
Upgraded to 32GB RAM total and now with same scene I am good. So far anyway. Expect to break that.
So, if i sum up :
- Iray is going to support rtx card soon
- More the gpu has VRAM, more you can load a big scene.
- More the gpu has cuda core, more the render is faster ( for the 10xx series, check the RT core for RTX series)
- RAM is not needed to speed the rendering, but without enought RAM you just cannot do a render
- 3dlight seem's to be for efficent to manage huge scene
- without working on texture definition, it's seems to be impossible to render big scene with a " little " hardware configuration
' Resonable ' is at least a render who dont fall back to CPU.
We don't know when Iray will support the RTX cors, nor do we know what effect they will have on render speed - however, the 20x0 RTX cards are fast as they are, so any boost from RTX will be on top of that.
Sorry Richard, i'v don't understand that point. when you say "when don't kown the impact", i've belevied you was talking about how the producer will have to adapt their way to create texture, lightning and how DAZ will adapt the subdiv techno to follow the RTX tecno.
regards
I mean we don't know how much the yse of the RTX cores will speed rendering, though ti seems likely it will do so to some extent. Nor do we know if it will increase (or decrease) the amout of GPU RAM a scene needs.