Adding a another graphics card to improve render times - Worth it?
RRed
Posts: 18
Hi All.
Hopefully this is the right place to ask but I have been reviewing a few of the other posts regarding improving IRAY render times by increasing the number of CUDA cores. Currently I have a GTX970 but was thinking of adding a GTX1050. According to the following pages it would add an additional 768 cores to the already 1664 cores. I am looking for less than $200 solution and the GTX1050 or GTX 950 seemed the best fit due to PSU limitations (I have 850watt psu, 970 use 500w so all those cards use 300w). I also use ths rig for gaming so I would prefer to keep the 970. This all started as I have access to friends old GTX 780ti but that is a few generations old now and I am not super keen or changing the PSU to 1200wats due to cost/practical reasons, its also really cumbersome (although lots of cores).
http://www.geforce.com/hardware/10series/geforce-gtx-1050
http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-970/specifications
This list is also helpful - https://www.studio1productions.com/Articles/NVidia-GPU-Chart.htm
I guess my question (is provided my PSU can handle the load) what will be the real world benefit for all the effort, what kind of gains would be achieved? What would adding another 768 cores do for render times? Does anyone else have a similar setup? I do understand that video ram doesn't play a part in render times but that the size of the scenes that can be handled and that the cards won't be in SLI as that doesn't work with IRAY.
Any insight much appreciated.
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Comments
Two things...
1. Yes the will be an improvement, how much is up to debate, as the current beta is just that, a beta and it's not really been optimized for performance. So, what happenss now isn't likely to hold true later (although I expect the actual gains to increase).
2. You will be limited to the card's memory...so if your 970 is 4 GB and the 1050 is going to be less than that, it will be dropped and those cores won't do anything. You'll be back to where you are now, just the 970.
There will be some improvement with a second card. It all depends on what you have. The newer Iray scales better and I have personally seen my speed double so its taking half as much time to render a scene. But I also have two 980TIs. One is running the monitor plus its rendering. I have yet to test them while running off my on board video as it should improve all the more if windows is not using it to display what its doing
mjc106 - Thanks, regarding your second point I got the impression from this post by Stardragon (and few others) that the card with the larger vram would hold the scene whilst all the cores would chip in, is this thinking incorrect?;
Mattymax - using the onboard gpu for display is an interesting idea!
I found this article that seems to suggests a group of smaller cards will beat out a bigger single card; https://www.pugetsystems.com/labs/articles/NVIDIA-Iray-GPU-Performance-Comparison-785/
From their findings in the conlcusion, doubling down on a single card type looks to improve render times roughly by 33%, but that is comapring like to like in terms of CUDA core amounts. Since the 1050 is about half cores of the 970 (768/1664) it would suggest a 15% imporovment from adding the 1050??? So a 1 min render would become 45 seconds? I am not sure if may maths works out ;]
Hey @RRed,
You can buy another 970 on ebay for about $175. That will give you another 1,664 CUDA cores, effectively doubling your peformance.
Your PSU should be fine for 2x 970's (depending on the brand). The card itself will likely never draw anywhere near 300 Watts under load. Furmark and other stress tests are worst case scenario's which most computers will not see. But if you are concerned, you can always get an Energy Usage Monitor to measure the power draw of your PC (only about $20 on Amazon). It should not draw more than about 700 Watts. If it does, you can always downclock your card a bit.
-P
If you have two cards...a 4GB one and a 2 GB one. Both cards will render 2 GB and lower scenes. Over 2 GB, the one card drops out...completely, it is no longer doing anything with the render. Over 4 GB, the other will drop and you'll be rendering in CPU mode only.
mcj1016 - Ah thanks I see what your saying, if 2 cards are not of the same VRAM amount the lower one can not contribute in the render process one the science sizes exceeds its max vram.
PA_ThePhilosopher - Having a look on Toms Hardware seems to suggest that 850w should be ok for two 970s. The Energy Usage Monitor is an idea too. I will have a look at the used market for 970s, as I would like to keep it under $200 and in my country new 970's are still at the $300 mark :( This may seem they way to go though, given the 33% increase would make the whole endeavor worth while.
Cheers all, big help!
Just be warned. We have at work 2 computers, which have used onboard gpu (i7 series) for display and on both of them CPU died in about 2 years time.
I do not know, if that was just a coincidence, but on all other computers I have installed dedicated graphic cards for display, just in case.
Performance is largely a factor of the Iray code, not the DS code. 2016.2 was a release build for Iray, so while there may be some refinement possible nVidia obviously felt it was ready for use.
Good to know. I dont think I will keep it that way if I get around to testing it out. I just want to see if it adds any real speed to the equation by letting both cards be 100% dedicated to rendering. I doubt the onboard graphics will handle the viewport in a large scene. I dont fancy having to switch back and forth either.
@RRed "I have 850watt psu, 970 use 500w so all those cards use 300w). "
You read your specs wrong. The 970 draws 145 watts. 500 watts was the recommended minimum PSU.
That 850watt should be able to handle a two video cards. I would go with a 1060 6gb and use your 970 for your monitors. I use a 1000watt and am using 4 high end video cards.
Fastbike1 / Silver Dolphin - Cheers, looks like I did grab the wrong spec, thats a relief!
In light of whats being said regarding on board graphics, I think I will leave it for now ;]
Related question regarding SLI for those with multi card setups. If I put the cards in SLI for gaming would DAZ have an issue with the setup or is it just something you can turn off inside DAZ itself? or does it just ignore it? As I recall IRAY not using SLI.
It's not Studio that has the problems with SLI, it's Iray itself. If you can disable it through Windows/software/etc then that works. If not then you may want to reconsider using it.
I've never had a CPU with onboard graphics die, whether it was the only GPU or in tandem with an NVIDIA card. My laptops have usually lasted 4-5 years before something else takes them out.
I've had onboard graphics die from other reasons...but not overuse. And usually it's not the chip that went. On one it was the connector (desktop)...never really felt the need to solder in a new one (motherboards are a pain to solder manually). Disabling it in BIOS and slapping in a video card was much quicker.
As to the laptops...4-5 yrs is a good run. I have a bunch of old, half working ones sitting around here that have had various problems and only 2 of them are graphics related, but it is a known issue with those models and a date with a heat gun usually fixes the problem.
Hmmm more research is required. Ideally I would setup both cards in SLI and then disable in DAZ as suggested to keep IRAY happy.