CPU-only rendering on a high end CPU and no GPU?
lambdalabda
Posts: 0
Hi al! I don't even know where to begin. The obvious search terms didn't help me, so please allow me to indulge in a lot of stupid questions.
I'm about to get a new PC and I've been wondering if I even need a GPU at all to produce at leat SOME renders. I know that a PC can run without one and do some basic stuff and so far all of my renders were CPU-only. I don't mind waiting a bit longer for the renders because I'm still just learning to light and pose for now, I'm just curious as to how a system without any GPU would do in DAZ. I'd only use it for rendering. I guess I could put my old GTX550Ti into the PC if it really needs at least something just for the software to launch, but for now I'm wondering about a CPU-only PC.
Would a PC with a very high end CPU and absolutely no GPU (or an old one) do better than a system with a mid tier CPU and mid tier GPU? I assume the opposite (cheap CPU + high end GPU) would just bottleneck and couldn't use the GPU to its fullest potential.
My budget can only afford a mid range setup if I go for the CPU+GPU route, so I've been wondering if pushing things to the extremes like this would make any sense? If there are specific benchmarks I should look up for setups like this, what would be a good one that compares to how DAZ3D works? Just regular CPU benchmarks? Or specific builds with specific benchmark softwares?
My main concern is that (if I understand this correctly) low-mid tier GPUs run out of VRAM all the time due to the scenes not fitting into them, so I couldn't do complex stuff with a cheaper GPU anyway. Where as CPU-only renders maybe work differently? I don't know, but I want to get into rendering more complex scenes with tons of objects in them.
I'm sorry about so many questions in one post.
Have a nice day!
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Comments
I use a threadripper, and have 980ti.
The threadripper is a decent alternative when the 980ti runs our of RAM (it has 6GB), which happens fairly often.
If you rende small scense, a dressed figure and a few bits then 4GB isn't too bad if you are only rendering on it, not using it for display too. You can optimise scenes so they fit, reducing texture sizes is the most important.
You certainly need to balance your system, but what will best suite you - only you really know.
The CPU only, is about takes about 15 minutes when the 980ti takes 5; I'm very glad of that shorter render when it happens.
I still haven't decided what to do about graphics cards; thinking about Octane atm, it seems a better option that IRAY, just more work. Octane are adding AMD support.
3delight is a CPU only render engine so you could render on it no problem but it will still take a lot of time. If you want to render on iRay it would be pitifully slow for most any scene with any complexity to it. I have experimented, just to see how bad it is, with having a very basic iray scene render CPU only on my R7 2700, which I guess would count as a high end CPU based on the sort of budget you're probably contemplating. It tooks hours to do stuff that my GPU took seconds to do.
Also keep in mind that if you try rendering a very large scene on the CPU you will fill up your RAM and that will result in lots and lots of disk swapping which will increase the time it will take to complete the render.
What I'd do in your boat is try my best to get at least a 1060 6Gb card, those are $250 right now. If you are willing to be a reconditioned or used one you might get one even cheaper. You might even find a 1070 in your budget by looking on the used market as well. Pairthe GPU with something like an R5 1600 which are pretty cheap right and a B350 MoBo which you can get for well under $100. Depending on what other components you have to bring over from your old system should let you get a fairly cheap system up and running that can at least render some stuff.
@kenshaw011267
"It tooks hours to do stuff that my GPU took seconds to do."
My old tower from 2007 with an Intel Core 2 Duo E6750 @ 2.66GHz can render simple stock scenes in 4-6 hours, so I thought that a good modern CPU could do MUCH better.
But if it still takes hours even with a good modern CPU, then nevermind the entire idea.
I guess I'll focus on a setup with a good GPU then.
Thank you for the reply.
@nicstt
"If you rende small scense"
That's just it, I want to tackle bigger scenes with tons of characters, so I'd run out of VRAM even with the most expensive GPUs. But I suppose rendering the characters in smaller groups is still an option to "cheat".
You're going to need scene optimizer even with a 1080ti/2080ti if you want to render battle scenes or the like all with genesis 3/8 characters.
https://www.daz3d.com/scene-optimizer
Some of the artists producing assets have a nasty tendency to produce seemingly innocuous props or wardrobe pices with absolutely huge textures. So even in a scene with only 4 characters set in my own outdoor environment I run optimizer just to make sure I don't run out of VRAM on my 1080ti which I'm pretty sure would have happened on a couple of occasions. I'm absolutely sure there are several scenes I've bought that if rendered as the default textures and materials are themselves bigger than 11 Gb with no added characters etc.
@kenshaw011267
That scene optimiser sounds great. I'll give it a try. Thanks.
I suggest browsing through the benchmark thread linked in my sig. A number of people have ran this bench on new CPUs, so you can take this test for yourself and compare. The results usually scale pretty logically, so if one CPU renders that scene twice as fast as yours, then you can probably count on it rendering the scenes you typically make about twice as fast as well. Use the SY bench on page one. And of course there are lots of GPU benchmarks and all sorts of combinations of CPU+GPU and other multiple GPU builds.
Even some of the lower end GPUs still render faster than most CPUs, unless you go really big on that CPU. But a Core 2 Duo, ouch, that is real old and only 2 cores. So yes just about anything would be better than that from your perspective!
You have some interesting options. What is your current machine RAM? A Core 2 Duo machine sounds like it might cap at 8GB, so you are probably not creating scenes larger than that. My old Core 2 Quad machine capped at just 6. Which in case a 1070 (which has 8GB) would offer a massive speed boost and run just about every scene you have ever made. You could probably even plug a 1070 into your current machine and render away just fine, as crazy as that might sound. I know of at least 2 forum users who have done that exact thing! I cannot recommend it, but it is possible, and you can run this while you save up for a proper new machine to eventually plug that 1070 into. Alternatively a 1060 with 6GB would also be a massive boost for you. Dude, coming from a Core 2 Duo, either of these cards might just make you giggle at how much faster they are, LOL. Perhaps you can find these users and ask them how things have gone for them since they did this. I know one or both posted in the benchmark thread.
Another bonus with GPU rendering is that your PC will be more usable during the render process, assuming you leave the CPU unchecked for rendering. But with just 2 cores, I cannot say for certain, you may still have to just wait it out for the render in order to really use the PC.
The alternative is to build out a new PC as best you can. You could buy a preowned GPU for cheap on ebay to test out the GPU waters, again using the benchmark thread as a guide to what speeds you could expect.
It is really hard to say though exactly what is best for you, you'll have to decide. Eventually you will need to build a new machine, but my idea of buying just a GPU now could be a stop gap to let you take longer to save money for a better rig. If you told any PC builder that you installed a 1070 into a Core 2 Duo rig they would think you are out of your mind. And like I said, I don't recommend this for a long term solution. But Iray is really funky, and doesn't really require the same balance that a gaming machine does if you stick to smaller scenes. However a good balance certainly does not harm it! Still, only you know what your budget can do.
ANSWER:
The way I solved this issue was to go into the Nvidia Control Panel and set the peferred Graphics Device for the daz studio executable to the Nvidia GPU Manualy. It was set to use my Intels CPUs integrated graphics automatically which forced it to render Iray using the CPU.
This right here! In Julyl I bought a new PC with a GTX 1081ti and it would kick over to the CPU having a scene with one character! It took me like three days to figure this out. I also turned off optix in the advanced tab as that was crashing my system every time a frame changed while making an image sequence. Now my system runs smooth as silk with these two changes.