Activeshade (V-Ray RT/Iray) Hardware Requirements - Can Low-end GPU meet them?

#1

Hello all,

I’m learning modeling, texturing, lighting etc. in 3ds Max & have recently come across videos demonstrating the use of activeshade in Iray, V-ray etc. I have a very low budget for a GPU (~$70 within which I could get a used GTS 450, GTX 550) but was wondering if a decent card can be had which will be enough for the realtime preview.

I read up on the Iray FAQ & have seen the benchmarks thread, but it all gives an indication of final production renders. So I’m wondering if there’s any difference in the hardware requirements when it comes to the activeshade preview.

For eg, for Iray to use the GPU for rendering the entire scene has to fit onto the Vram. Is it the same for the activeshade window?

For eg, in Iray the better the GPU, the lesser the rendering time. But for the preview, if one is prepared to live with a certain amount of lag, will a lower spec card be much different than a higher spec card?

I currently have a Core i5 2400 & an ancient 8600gt 256mb ddr3. Right now, my CPU is much faster than my GPU when it comes to activeshade. So can there be a significant performance increase with a GTS 450 or GTX 550 & the like? Can I expect a much cleaner result than the one attached (activeshade rendered by CPU)?

Also, how much Vram is ok for a beginner? In his blog post, Jeff Patton has attached an image which was rendered in Iray & took up about 900mb. Judging by that, it seems like 2gb will be more than enough for a beginner.

I’m guessing there’s not going to be a concrete answer to my queries. But I’m hoping someone has some experience with these or similar cards & can help with some basic guidelines to be kept in mind.

Thanks for your time. Much appreciated.

#2

The VRay specific questions you’d be much better off asking in the Chaos Group forums to be honest.

As for the videocard, there’s a very big jump between an 8600 and a gtx 550 ti, particularly on the CUDA and OGL feature set and memory bandwidth, not to mention amount of memory, so if a second hand 550 ti is all you can afford, well, it would be a considerable jump.
Whether it will beat your CPU or not is hard to tell, but in pure number crunching it should.

The 8xxx series were CUDA 1 and 1.1, the 550 ti has CUDA 2.1 support and a much wider memory. That alone is a considerable jump. The architecture itself was also a big jump.

For 70 bucks it would be a considerable upgrade for a number of things.

#3

Thanks for your reply.

I wasn’t really asking about V-ray RT specifically. Rather I’m more interested in the activeshade rendering, be it Iray or V-ray or Nitrous.

Probably what I’m asking is whether the activeshade requires fewer resources. So if a scene requires 3gb of Vram for Iray to render via GPU, is it the same for activeshade?

In terms of final production rendering, you’d want to eliminate all noise from the final image. Therefore, to get reasonable render times, you’d want the absolute best card. But for activeshade, is it more like FPS in games where a lower spec card will lag more?

As for comparing a 550 ti with a Core i5 2400, isn’t there a magic number like say, FLOPs or so which will help gauge performance? Or there can’t be a comparison since they handle different tasks or work differently?

Again, I can totally understand if there are no accurate answers. What I’m asking is pretty ambiguous & one of those YMMV scenarios. But probably best to sum up by asking if the activeshade preview in Max works differently to the production render?

Again, many thanks.

#4

I recently submitted this post:

http://forums.cgsociety.org/showthread.php?f=23&t=1122269

#5

Vray doesnt render in activeshade. It renders in the frame buffer (either Max’s or Vray’s). Vray RT (or Iray) renders in the activeshade window, in either CPU or GPU mode. Nitrous is the viewport renderer. You can very well use Vray RT or Iray for final renders, as long as your scene doesnt use unsupported features, fits in vram and provided you let it bake long enough to get rid of the noise.

#6

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