980ti vs 1080ti for of course.... iRay

[deafx]

Hello guys

I'm thinking about switching my dual 980ti setup for a single 1080ti. I could probably get a good price for my current cards, and the offset isn't that bad. I'm satisfied with the render speed I'm getting with the two 980ti but VRAM is an issue with complex scenes and I'm a bit tired of having to go around this using different strategies, it's time consuming and honestly very frustrating.

Right now I'm using the Intel integrated graphics in my CPU to drive my two 24in monitors... letting both the 980ti free of any 2D stuff. So they have an effective 6Gb of VRAM for rendering. It's not bad, but I still have issues... And I can't game with this setup...

So to my question: the new 1080ti has 11Gb of VRAM. That's huge. But I can't find any information on the performance compared to two 980ti for iRay rendering. I read stuff about how a 1080ti will outperform two 980ti in SLI in some games, but it's not really relevant since it's based on SLI and iRay doesn't use SLI.

Any thoughts? Do you think it's close? I would think the two 980ti are a little bit faster but I can't say for sure... I just don't want to loose too much...

[Anonymous]

The only place I've seen GTX card comparisons are on the DAZ forums.

https://direct.daz3d.com/forums/discussion/53771/iray-starter-scene-post-your-benchmarks

And see this for Windows 10 VRAM problems.
Ignore the fact the OP uses Octane, it seems to be either a Windows 10 or Nvidia bug that won't allow your GPU to use all VRAM.

https://social.technet.microsoft.com/Forums/en-US/15b9654e-5da7-45b7-93de-e8b63faef064/windows-10-does-not-let-cuda-applications-to-use-all-vram-on-especially-secondary-graphics-cards?forum=win10itprohardware

Also consider 2 Maxwell TItans over one 1080 ti since they are cheap.
And also consider the cooling requirements because I can BBQ chicken on one rig with 2 Titan Z cards unless the fans are turned up to 11!

[deafx]

Yeah, I've looked into that thread in DAZ forums, it gives an idea but numbers don't always make sense. I tested this scene some time ago and my renders were much faster than others with a similar setup. Unless someone tested different cards on the same (or similar) gear, it does really help.

I'll have to investigate this Win10 bug because... sometimes both my cards drop from the render for no reason. That could explain it. It looks like the VRAM should be enough to render the scene but the cards drop anyway. The problem is, there's no fix, and it looks like MS don't give a shit. 🙁

And about the Titan X Maxwell cards, they are mostly the same as my 980ti but with 12Gb. The Titan maybe a bit faster with 10% more CUDA cores. I can find some for around 600-650$ used. That's 1200-1300$ for 2 cards... More than a 1080ti and maybe not a lot faster........ I think. But not totally sure as this was basically my question about performance.

[deafx]

I just retested the scene and got 1.37 sec with 2 980ti...

Some guy with a recent build did 2.04 with a 1080ti. Another got 1.52. So yes, the 1080ti is slower than 2 980ti. Not much though.

[deafx]

Well, I ordered a 1080ti.

One of my 980ti went up in flames yesterday. Not even a figure of speech, it actually made a "puff" sound with some burning smell... And the PC rebooted with a "surge" warning in the BIOS. Yup! There she goes...

The card will go to Gigabyte and be fixed under warranty, but it gave me the "signal" for ordering the 1080ti and sell the other 980ti. I guess life kinda decided for me! 😉

[Anonymous]

Sorry to hear about your 980ti (RIP for now)
Was it air cooled, overclocked etc? If so this may be a factor in it's demise.

I guess you are going to sell the 980ti's from what you've said?
Might it not be better to keep one as a second card for iray?

I know we are not all made of $'s, me especially. But it may benefit you in the long run if you have a separate gaming rig from the one you want to use for 3D applications. Gaming hammers the cards into the ground and with all that heat they have a shorter lifespan.

Just a though 🙂

[EvilMonkey]

This was really interesting to read through and follow along. I'm sorry @irsnout but i laughed out loud when I saw you'd bought a 1080ti after talking yourself out of it. I'm sorry for you losing a card though, that sucks.

I'd suggest doing some render testing of the 980ti vs the 1080ti if you've got no urgent need to sell it. And maybe even as @norbertz said, keep the card to run as a separate driver for iray and see how it performs. It may even beat your Sli setup...

Whatever you do I hope all your components stay safe! 😉

[Anonymous]

**Thought**

I will spell check before I hit the submit button in future 🙂

[Anonymous]

It's a shame iray won't utilize the CPU along with the GPU's. We'd have a small rocket ship rendering rig then.

And all that trouble with Windows 10 not making the GPU's fly as they should is a kick in the teeth.

[deafx]

I got my 1080ti. As expected, a little slower than the two 980ti, but I have more room for textures.

Weird enough, it looks like it uses more VRAM if I compare scene to scene. This may have to do with the fact that the more VRAM you have the more Win10 will reserve. Which doesn't make any sense.

I'm thinking about going back to Win8 or even Win7 but... it's really not something I want to do. I hated Win8, and Win7 is getting old. 🙁

I don't understand why they don't fix their shit. This problem was reported a year ago!!!!

[Anonymous]

Can you set up a VM with Windows 7 and test for that VRAM issue?

Yes It's a fix that Microsoft should make a priority since the gaming community is a multi billion $ industry.

[deafx]

To my knowledge it's not possible to do what you described with HyperV at least. Not sure if it's possible with other virtualization software.

[Author]

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