GPU Rendering vs. Core rendering

#1

Hi,

I’m wanting to build a PC mainly for AFX, Maya, Blender, etc. I can probably build whatever I need but the foremost question here is: With the recent GPU rendering that softwares are beginning to adopt, does it make sense to build a system with maxed out rendering cores or a dual SLI/Crossfire badass graphics cards system?

Now here is what I’m VERY tentatively thinking of comparing for those who need specs to answer this questions. It’s a general question but people still get hung up on specs for some reason when I ask this. Here it goes:

CURRENT SYSTEM:

2007 Mac Pro (before PCI 2.0! which means I can’t utilize newer video cards)
Dual 3.0 ghz Quad-core Clovertowns.
16 GB of Ram
Radeon HD 5770
7200 rpm hard drive
Stock Mac pro motherboard with PCI E 1.X

O.k. so next are the 2 systems I could build:

#1
3.4 ghz or 3.5 ghz Quad-Core Ivy bridge CPU overclocked to 3.8 or 3.9
16-32 GB of Ram
Compare
AMD FirePro S7000, Nvidia Titan or 690
1511 Motherboard
Be able to triple boot into OS X, LINUX, WINDOWS 8
Watercooled

VS.

#2
Dual 3.3 ghz 6-core Westmeres (can’t overclock xeons)
16-32 GB ram
EVGA motherboard
A decent but not greatest or newest AMD card
watercooled

With graphics using the video card more and more in the future I’m wondering if more cores for rendering is not a more popular choice anymore. #1 is potentially just as expensive as #2 but only as much so down the road as I don’t have to up front buy both video cards where as I do have to with a dual processor system. With #2 I almost feel like asking if the 4 extra cores are even worth the upgrade whereas with #1 I feel like I can mold it as technology changes (because I’m not stuck with the EVGA motherboard which is a super specific motherboard) and that the loss of 4 cores is not a big deal with the gain of killer video cards. PLUS, there will be 6-12 core Ivy Bridge cpu’s released in 2013.

What do you guys think? Do you think GPU rendering is the way to go and that multicore CPU workstations are not worth it as we move forward? Or do you think that GPU rendering has a long ways to go and that multicore will still be king in the next 5-6 years?

#2

Overclocked I7-3930k (6 core). There are still some features that gpu rendering can’t do, but I know the guys at cg-architect love it. From what I’ve seen nvidia 5xx and 6xx are the top for cuda processing (things may go to opencl but it’ll be a while from now). The titan looks very promising. With the i7-3930k and x79 chipset you can easily have 3 video cards, and cuda programs scale with the amount of cores (more cards = more cores) so if you need more power just add another 680 or 690.
I hope gpu rendering takes off, it’d be nice to see realtime raytracing.

#3

Hey man,

Vray is still king in the arch viz world, but iRay really isn’t a bad solution for quick renders where things need to look good, but not insanely detailed. I’ve only seen people play around with it, and it still has some limitations for total photo realistic work.

Getting that i7 6 core and a large MB with 4 PCIx16 slots would be a great foundation for a new build. I’ve read on the forum that iRay will use multiple GPUs, but doesn’t require SLI or CF.

-AJ

#4

I heard they were coming out with ivy bridge 6 cores - 12 cores throughout 2013. So maybe I will wait on that. They also have an 8 core sandy bridge. EDIT: What this says to me is that maybe a quad core slower ivy bridge is best and then sell and replace that cpu with the ivy bridge 6 core - 12 core sometime this year or just wait.

Thanks for the heads up of development of iray. I mean, there are plenty of software packages that are stepping up. Mental images iray, V-Ray, Blender’s Cycles is certainly no slouch (although sorta slow), Luxblend, etc.

So are these top 2 posts in agreement that possibly the high multi-core CPU processor for rendering may be becoming extinct (certainly not dead yet)? I just might go ahead with this GPU build.

#5 
  Those Intel 6 core chips are a great foundation to any 3D workstation build. Its always a good idea to get a MB with lots of expansion room so you can upgrade. The new ones should be coming out later this year.
  
  CPU 3D rendering will not be going extinct. GPU rendering will definitely be getting more popular as the software gets better though. If the stuff you can produce with iRay or another GPU renderer meets your needs quality wise at this point, then definitely load up on GPUs. But keep in mind its not a replacement for Vray or MR.

So in other words, try to think of them as two different solutions. MR and Vray give you lots of accurate and complex rendering algorithms to work with, but are slow. iRay and other GPU renderers are much quicker, but your more limited in your options to help your renders look their best.

  -AJ
#6

Like AJ said, the cpu won’t be going anywhere. If you have 4 video cards, you’ll need a cpu powerful to prevent bottlenecking, it needs to be fast enough to tell all of them what to do. Vray RT uses the GPU, but I don’t know much about it. For your build though, getting an x79 chipset motherboard will be the way to go because, for the next 1-2 years, intel’s extreme cpu’s will be released with that lga2011 socket type (aka you can upgrade).
I’d get the i7-3930k with 32gb of ram, a good x79 motherboard that allows 3-4 video cards, a gtx 680, or 690, or two of whatever you want. Check out the cinebench scores, you can get the 3930k up to 12-13 whereas the 3770k is 7-8.5. If you do GPU rendering it would be smart to have at least two so you can dedicate one to rendering and use one for working on. I don’t know about gpu network rendering, but most people here will say it helps to have at least one render slave (less important if you’re just doing stills).
Check out forums such as overclock.net, tomshardware.com, reddit.com/r/buildapc or /r/gamingpc to get details on what specific parts would be best.
Good luck!

#7

Hi AJ!

Thanks very much for the replies. I think I understand. I would like to point out that Luxblend is an unbiased renderer, ala Maxwell (is that even alive anymore?) and luxblend uses GPU rendering. It is really only for single renders because of the long render times.

I’m reading up on this because apparently I don’t know as much as I thought. For example, The 6 core Sandy-Bridge has 12 threads. So in MR, when you go to batch render dialogue and it asks for threads, can you put in 6 or 12?

How much better is the computer CDenny suggested, as far as core rendering, than my old box?

If I didn’t feel like making a Hackintosh out of it, would I be able to link a windows computer and Mac computer together in Vray or MR so my 6 year old box could use it’s 8 cores to help with rendering?

Thanks guys, you’ve been champs. After being out of hardware wars for so many years this stuff is a lot to catch up on.

#8

Also, how many watts psu am I looking at?

#9

I use V-Ray for Maya all the time but I don’t even bother with GPU mode for V-Ray RT because it’s too limited (shader limitations) and unstable compared to the CPU mode. GPU rendering is overrated and inflexible. You’re basically burning the planet down for a novelty that wears thin quickly. Also, V-Ray RT OpenCL has issues on AMD GPUs.

My $0.05 (we are no longer producing pennies in Canada).

Hardware-wise, I wouldn’t bother with Westmeres at this point. Overclocked Ivy Bridge i7 3930K or wait for whatever Xeons the next Mac Pro and equivalent PCs stock.

#10 
You would need to set that at boot time. Its a setting that you change in your BIOS. Its more efficient with more threads, so you should leave it on. You can use render flags in backburner though to only allow it to render on a certain amount of threads.

http://forums.cgsociety.org/showpost.php?p=6260644&postcount=2

Probably more than twice as fast. Hard to say though.

Windows and Macs work just fine together in distributed rendering.

As far as your PSU goes, you should get a pretty big one if you want to load up on GPUs. Probably over 1000w. But you could always just by a small cheap one to start out with.

#11

According to this database, http://www.cbscores.com/ when I look at the xeon x5365 it’s 3.16 for one cpu and around 6.33 for two (it’s listed as 8 cores/8threads). You can also see the score for the 3930k, they’re around the 11-13 range, so I guess it would be twice as fast. I just upgraded from a phenom II x4 to a x6 1090t for $120 and I get a score of 6.7, so your system is showing it’s age. Doing test renders showed that it scaled linearly with cinebenchs scores (score twice as high, renders twice as fast). Other factors such as ddr3 may make it even faster.
As for wattage, that is largely dependant on how many video cards you have, but if you’re looking into multi-gpus it’ll be around 1000watts. Using pcpartpicker.com is useful because it gives you a wattage estimate.

Windows and Macs work just fine together in distributed rendering.

Yes, but I’ve had friends have problems with network paths, one uses \ whereas the other uses / There is a solution, just be aware that it wont work as smoothly as it would if everything were the same os.

#12

I don’t know of any renderers that need to access shared textures via mounted absolute paths. V-Ray was the only one that did and the recent nightly builds do automatic asset transferral on the back end between OS X, Linux and Windows, with no problems:

https://vimeo.com/50444501

I use a Mac OS X host, a headless Linux box and a Windows gaming machine in V-Ray for Maya renders and it’s flawless and perfectly stable. mental ray and other renderers have a similar asset transferral, so I’m not sure which renderers still have problems with absolute paths.

#13

Well, would a 1200W PSU be sufficient for at least a couple of cards with this setup? I dunno, maybe I can snapshot my newegg parts and leave the PSU for last to ask one of you guys. I really have no idea. I’d rather do one that is 950W because it’s cheaper.

#14

O.k., Cool.

Sounds dumb but I’m thinking that I’ll never throw away computers again. Even if I can get a dinosaur to run a few frames here and there, that’s good for me.

#15

CGBeige:

Ivy Bridge i7 3930K? That’s a Sandy Bridge. Just making sure. The Ivy Bridge 6-core doesn’t come out until the end of this year it seems. Too long for me to wait I think.

Thanks for your .05 cents. I know you are a rendering buff here on CGsociety so I value your opinion. I don’t necessarily think you are wrong but to point to V-Rays shitty shaders have nothing to do with whether GPU rendering performs better than CPU rendering and whether it will overtake in the future. LuxBlend is an unbiased renderer with great shaders. It uses GPU rendering. I’m not stating anything except that it’s the developers faults for not developing good shaders.

Aside from that, it seems I need a new computer anyways so your opinion has helped me maybe pull the trigger on this build or something similar because whether or not GPU rendering is the future, this computer build will probably cost around half and be twice as powerful as my current.

You can also see the score for the 3930k, they’re around the 11-13 range, so I guess it would be twice as fast. I just upgraded from a phenom II x4 to a x6 1090t for $120 and I get a score of 6.7, so your system is showing it’s age.

Wow, thanks for this. It’s hard to part with something you spent a lot for even when it’s age is showing. Guess I am seriously thinking about this build whereas I was tentatively looking at it.

Thanks CGBeige, CDenny and AJ1! If anyone else would like to comment, I appreciate the ongoing convo.

#16

950W is plenty unless you’re running a pair of old Nvidia 5xx cards.

V-Rays shitty shaders have nothing to do with whether GPU rendering performs better than CPU rendering and whether it will overtake in the future

It’s not V-Ray’s shaders that suck, it’s that you don’t get as much support for Maya’s procedural nodes in GPU mode. Once you start to build more complex shaders with utilities like blendColors, multiply/Divide, +/-, sampler info, etc. RT GPU falls apart very quickly. It’s just that making stuff work on the GPU is very difficult, so it takes longer to support. You won’t get these types of shader nodes in furryball, Arion, Octane, etc. because they use a straightforward progressive path tracing ray trace and don’t have a lot of flexibility (that’s why all GPU renderers basically look exactly the same). If all you want is a quick preview of some metal or car paint materials and a sun/sky, you should be fine but if you’re looking to do out-of-the-box VFX stuff, leave GPU rendering out of the equation. The GPU can be really handy for certain things but it’s not a one-stop shop like the CPU is.

#17

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