I Added Cuda Cores
laststand6522732
Posts: 866
I was wondering what it would be like to render IRAY fast, so I added a 980ti today. I'm testing now to see how much speed I picked up. I'd like to share my results with other users. My numbers are approximate. My IRAY setup was hacked rather than carefully planned.
- Test Image Size = 791p x 753p
- Scene contained clothed figure only
- IRAY Settings shown below
The machine has an I5 quad with 32G. HD is SSD. Old video card (Quadro K2000, 384 cores) left in place to drive monitors. The new card added ~2800 cores. The additive result of these cores being linear, or so I've read, I was looking for an 8x speed increase. Even 4 would have been cool. I was also looking to see my viewport update in near-real time, like the YT video shows. There is no noticible improvement in viewport update speed.
Speaking very roughly, the image renders in 4 minutes now instead of 8. CPU usage remains ~65% during render, even though CPU is not selected in NVIDIA Advanced Settings. I'm not over the moon with these results, and considering all the ranting and raving I see about these cards, I'm a bit surprised. Maybe I've done something stupid, and you'll spot it and point it out to me. Otherwise, if you've been pining for one of these cards, as I was, this is what they do.
I'll be interested to see your comments.
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Comments
I would suggest going to this thread and posting using the baseline there. There is alot going on in Iray if we don't use a baseline it is hard to tell what is slowing you down.
http://www.daz3d.com/forums/discussion/53771/iray-starter-scene-post-your-benchmarks/p1
Oh, by the way nice render on devil girl ; )
1. Are you positive the 980 is actively rendering? You need to check the troubleshooting log, and look for warnings and errors. It will tell you the percentage each device contributed to the result. You should also install and use a VRAM/GPU monitor, such as GPU-Z, for verification.
2. It is said that mixing consumer GeForce with Quadro cards can cause issues. Nvidia says the drivers may negatively interact when installed (and used) together. If you're not having any problem, then there's no need to change anything. But if you notice instabilities, or features you expected in one or the other not working, you might consider taking the Quadro out and replacing it with a basic 1GB GeForce that can share the same driver as the 980ti.
3. When properly set up, you should definitely be seeing a healthy speed increase with the added 2800 cores.
Are you taking in account the overhead in loading and preparing the scene? If not you should becuase that will not change.
example, also maker sure that the K2000 is not selected and optix-prime is off.
K2000 980TI
LOAD scene 30s 30s
Render 7.30s 3.30s
total 8.00m 4:000
This may have been an nVidia driver issue. I made a lot of changes this week, including video drivers. The test render time is down substantially. Now I'm impressed. NEVER trust Windows driver update utility. Checking and updating manually produced drivers a year newer. Iray render time is down to about 1/4 of what it was. This is more like it.
Thanks. That's Eevelyn.
This is interesting. It had crossed my mind. So far I don't see any evidence of this, although before I got the drivers right, I did have video-related issues in other programs. Skype, for example, suddenly couldn't see any webcams. I'll be keeping an eye on this. Thanks.
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Later...
I now suspect "bottlenecking."
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I'm a gamer and I have the "Geforce Experience' installed. Its a program that makes sure your drivers are up-to-date and will alert you when a new driver is available. It's by Nvidia - not a 3rd party program. WOrks wonders for keeping your cards in tip-top shape.
Thanks. I'm acquainted with it.
What SEEMS to be my problem is called "bottlenecking." This occurs when the GPU wants to process data faster than the CPU can cope with it. The symptoms are unusually high CPU usage, which I have observed, and little or no speed benefit from the GPU. It would not surprise me a bit if my CPU is holding back the show. It is an I5 3550, about 4 years old, with a mere 4 threads. I never had to put such a fine point on hardware performance before I started fooling with 3D. I have to say that if it wasn't for what the marketing people call "gaming," there probably would be no advances made in PC hardware at all.
I'll be testing CPU and GPU performance a little more before acting on this, since this is not a cheap fix. Eventually I'll post the results here.
"Speed costs money, son. How fast do you want to go?"
What PCIe slot does your PC have? The older slots cannot shuttle data as fast.
The K2000 is in slot 2. The 980ti is in slot 5. The terminology they use is mumbo-jumbo to me.
After reading this, I found the note below. I'm not completely clear on this. If by GPU they mean the GM200, the options are limited. If on the other hand they mean the Maxwell architecture, the GTX 750 would be an affordable option. Which do they mean?
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OK, I found the list. I'll be able to find something affordable here (under Supported Products). A common driver makes a lot of sense regardless of whether bottlenecking is a factor. Thanks.
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I went with the GTX 950.
Iray is designed to use the Primary card for its initial load. you will need to put the 980ti on slot2 as it will load that first. and put your old card on slot 5
aHA. If both slots had the same specs, would one still be "primary?"
I'll change these positions later in the week when I install the 950. Then I'll take another look at performance. Thanks.
I have 2 970's and have both selected and yet iray will only use the First (primary) card to load all of the information into (thus the VRAM restriction to 3.5GB rather than 7GB) once all the CUDA info is loaded it will then use both cards to Color unless the primary card was overloaded (More than 4GB Memory) then it switches to CPU
However..... I think this has changed with the Latest Beta that has the newest iRay version which appears to take advantage of Both VRam cards... although I could have been seeing things when it said 6.5GB Memory Load and Still used the GPU's
To "close the loop," as they say...
The 950 is in, and the Quadro is out. The 950 and the 980ti are using the same driver. This is a smooth operation now. A handful of tiny little Windows things improved, things you might not attribute to two drivers struggling. Average CPU usage is maybe half of what it was. CPU temp is down a bit. The most noticible improvement is the speed with which the viewport is repainted in Iray mode. You will see the repainting take place, but you won't wait very long. It's pretty close to the nVidia marketing video. It's much easier and more fun to work with now. This alone was worth the cost and effort. I haven't done any timed renders yet. Obviously there was more to that driver business than I realized.
I held the cost down by using factory refurb cards. They work fine and they're on warranty. Most electronics that fail before their time do so in the first 24 hours of use, so if it lasts a week, you've got it made. The two cards came in under $500, and the 850W PS added a bit to that. If you can justify this kind of expense, you'll get response you can really see. There is no observable noise increase even though I added five (!) fans to the box.
My thanks to Tobor for getting me on the scent.
If you use iRay in your viewport, you might want to check the Draw Settings panel under the "Drawing" section. Everything in there will affect the render speed. I personally use "Blend Interactive to Render settings". I've bumped up the response threshold to 500ms though this can be adjusted to personal preference. Manipulation resolution can be turned down a bit to get a faster response. Play around with it and you can get super fast updates in the viewport without going to the dreaded gray materials.
UPDATE
This week the refurb GTX 950 I had in place croaked. I took it out and connected my monitors to the 980ti. The speed of Iray rendering increased quite a bit. I have no explanation for this. I'm not complaining though. The only variable I can see that *may* have been at work was Wallace3D's comment about which slot was used on the motherboard.
If you had the 950 also selected for Iray in DS, that would explain the slowdown. When multiple cards are selected, they will tend to 'level' each other out, due to PCI-E bus contention as well as cache-coherency between the cards. Having a slower card working with a faster card will often be slower than simply running the faster card alone. Best to use the slow card JUST for the display (make sure it is unselected in the Iray settings in DS) and use the fast cards for Iray.
The 950 was not selected for rendering. The cards were set up as you describe.
Sorry to hear the card died -- was it too much heat? You often have to install at least one auxillary exhaust fan to move more air through.
Where do you get your refurbed cards? I look around, and don't know which ones to trust.
As to why your render was slower with the monitor card installed and not used for rendering, I couldn't say I fully understand that one. But CUDA and Iray follow their own laws of reason, so you never know! There might have been some interrupt hanky-panky or other data management issues; I'm not sure how to test that, other than to swap stuff out to see what works better. Out of curiosity, which slot was being used for the 950, and is your PC PCI-E 2.x or 3?
I kept an eye on the CPU temp and fan speed. When Iray was engaged, CPU temp was 55C-ish. It did see 60 at one point. It would have been worse if I rendered a busy scene. Failure was instantaneous. Screens went black, power stayed on but could not warm boot, had to cold boot to fix it. After a time or two I could recreate it. Put the viewport in Iray, then press RENDER in Iray so as to give the system two tasks, and it went immediately. It was fine for a week, but then got sickly. I think one component was marginal and I pushed it. I left the 980ti in slot 5, it's so long that if I put it in slot 2, it interferes with my hard drive cage. I had the 950, which was a half inch shorter, in slot 2. Both are 3.0 slots.
I get refurbs at Newegg. They are factory refurbs with warranties. They issue an RMA without question, although I did end up paying the postage. The cost difference is great enough that to me, it's worth taking a chance with them.
Now I can render an 800p sq. image with only a figure and a floor in it in less than 30 seconds. This is maybe 1/3 what it took before. It's a tad grainy because I have the settings turned down, but it may be OK for video. The viewport redraw is right snappy too. For the time being I'm happy with it. It's good enough to make Iray actually usable.
It's just got a puny Zallman HS on it now. I'd like to keep the CPU under 50C. I've got a new Noctua NH-D15 that ought to take care of that. Unfortunately I'll have to take the motherboard out to install it, a job I'm not looking forward to.
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The GPU temp is the only sensor the card reports, but it's not the only failure points on the card. Other components, not cooled, can be affected by a high ambient temperature inside the case. There are some third-party temperature sensors that can report the internal case temps, but the cure is always the same: get more air through the thing.
Good to know your rig is able to process scenes in so much less time. That's the main thing (well, that and not blowing out graphics cards!).
I can't say for certain that heat wasn't an issue in the card's demise, or for that matter, in its performance. I wasn't monitoring the card's temp. I've since installed GPU-Z, and the 980 is at 46C now, which I understand is comfortable. I've never had to monitor heat before.
Most cases aren't designed to dissipate the heat from two or more graphics cards. The heatsinks on each GPU and the CPU keep those components reasonably cool, but the heat has to still get out of the case.
Yes, you're right. Case design is pretty much what it's always been. That probably explains the popularity of liquid cooling. There's no more room for fans. I will say that this time of year, I appreciate my small home office being the warmest room in the house. :-)
Well, I've had enough of refurb video cards. The 980ti cashed in its chips last night. And this time I was monitoring temps. Fortunately I had my trusty Quadro K2000 to reinstall. At this point I give thumbs down to refurbs. As an educational experience, this has been cheap.
According to one comment in this thread, "...it seems that when mixing cards, the faster cards match the speed/performance of the slower cards." If so, it would explain my speed experience. Iray for the common man may be a work-in-progress.
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A pair of GTX 1070s would cost the same as a new GTX 980ti, but they would exceed its RAM and CUDA specs. I am considering this.