Gpu vs cpu

[glorybound]

I think RT is still some kind of unicorn to most. People are buying GPU's, thinking that they'll whip through scenes like nobody's business, however, I think it might be a misconception. Unless I am mistaken, we are still limited to one GPU, correct. I had one dedicated to my monitor and the second was for V-Ray. If your scene won't fit into your single GPU RAM limits then it's a moot point; it won't flow over into a 2nd or 3ds card.

[glorybound]

Also, you have to build your scene to be rendered on your GPU because many things are not supported. I tested hybrid rendering on an interior scene I am working on and I am getting Fresnel reflection errors and my highlights are blown-out. Now, if you could run a script to set your scene up for RT, that would be awesome.

[Alan Iglesias]

I'll read earlier. Are there any setting I should tweak to improve GPU render times?

Bobby, another good reason to use RT/GPU as the Production Renderer when Hybrid rendering is the default Brute Force/Light Cache usage. Much faster than BF/BF in active shade.

-Alan

[Alan Iglesias]

I think RT is still some kind of unicorn to most. People are buying GPU's, thinking that they'll whip through scenes like nobody's business, however, I think it might be a misconception.

Bobby, FYI, everyone I know (and that is a considerate amount of folks) who has bought GPUs for production rendering did it only after testing and proving their workflow with RT/GPU.

Just to let you know that there are plenty of work-horses to go with those unicorns...

-Alan

[JezUK]

If I can chime in here - the last major project I did, I decided to go with RT all the way - and specifically bumped up my 2 x 1080 ti's to 4 x 1080 ti's just for this one project.

I found I needed to do a *lot* of tweaking of materials to finally get RT to render without crashing, but once I did get all those out of the way, the speed improvements were *definitely* breathtaking.

Not only that, but I love the visual interactivity RT and GPU rendering affords.

So, for this project I mention - my 4 x 1080ti's were churning out renders in 6 minutes in RT (4 x GPUs).

Once the project was delivered and I had time to see how long CPU Adv rendering would have taken, I found my no-slouch 5960x would render that same scene, same noise thresholds etc in 26 minutes.......

6mins vs 26 mins is what I found.

I reckon your Dual Xeon is about twice as fast as my 5960x (by memory as my work last year had those Xeons) - yet you only have ONE 1080 ti.

Answer.... you need more 1080 ti's my friend.

PS - I often read that RT doesn't support this or that, but I have to say, that in my case, those unsupported features aren't deal-breakers (I don't need them anyway) - so for me RT is a very worthy render engine that is going to be my default go-to renderer as much as possible.

NOTE - RT is a different render engine, so you *will* get different results coming out of the box and those results may or may not be to your liking - for my clients, who loved what I did, I know they aren't really interested in the details we can see (and they can't or aren't bothered with).

PPS - I also found that CPU & GPU wasn't faster, but slower and I was told that my CPU isn't a good match for the performance of my GPU's - that doesn't make sense to me, because from my simplistic point of view, I was of the belief that the "more hands to the pump" the better....

[glorybound]

Yes, I need more video cards. I was thinking about ordering a new case that I could drop my motherboard in that supports more video. Right now my one 1080ti is too large for my case and I can only have two and I am not even sure my power has enough power to power two cards. Maybe, I just need a new computer altogether, however, I just dropped $6000 on this one a year ago.

[Syclone1]

Be careful buying a new case for your mainboard, have a close look to make sure that Dell hasn't changed the mounting pattern to prevent that sort of thing. I know they used to have different pin outs on the PSU and if you dropped in a standard PSU it was sure to blow up so you were forced to buy their... stuff lol. I do feel your pain about the video card not fitting, I have a HP Z820 at the office and have to leave the side off and one of the internal vent things as the card I have in it is too big.

[VelvetElvis]

If you are getting into the need for many cards, you might as well build the system yourself and save at least 30% of the cost of a big name system like Dell.

Deciding to go GPU all comes down to where you really save time. If each scene takes extra time to get it to render nicely on your GPU, are you really saving time? You save render time but you increase your scene prep time, so it all becomes moot in the end.

[anthonyh]

I`m hoping the amd threadrippers will help instead of going gpu. of course it`ll mean buying some new machines.

[glorybound]

I remember when an interior would be an overnight ordeal and now I am getting them done in an hour. I still have nightmares of waking up to find errors or crashed nodes. I am content for awhile and I'll work this machine into the ground. Typically, I use a machine for around 3years. The next one will probably be GPU heavy.

[BBB3]

Be careful buying a new case for your mainboard, have a close look to make sure that Dell hasn't changed the mounting pattern to prevent that sort of thing. I know they used to have different pin outs on the PSU and if you dropped in a standard PSU it was sure to blow up so you were forced to buy their... stuff lol. I do feel your pain about the video card not fitting, I have a HP Z820 at the office and have to leave the side off and one of the internal vent things as the card I have in it is too big.

Tell me about it. Z820 is so bad for GPU computing. I can only fit one 1080Ti in there, even though the PSU could handle two easily.