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Memory in Graphics cards - better 2x3080 with each 10 GB or 1x3090 with 20 GB?

Posted: Sat Oct 10, 2020 9:27 pm
by Theo_Gottwald
How is it seen from the standpoint of rendering possibly complex scenes?
FROM the price a 3090 is not far from 2x3080. Generally 2x3080 have in total more Execution Units.
Can in Parallel make more calculations then 1x3090.
But using "Out of core" Rendering because the GPU RAM is not sufficient, makes thing a lot slower.

Also if the GPU has 20 GM RAM, you can make larger Tile-Sizes and better use the Parallel Capabilities of the GPU Hardware.

So which Combination do you expect to be better for Rendering?
Any Ideas?

PS: They are not really available at this time below the price of a car. But with time these cards may get available.

Re: Memory in Graphics cards - better 2x3080 with each 10 GB or 1x3090 with 20 GB?

Posted: Sat Oct 10, 2020 10:46 pm
by Sharlybg
There are a lot of justified rumor about 20Gb 3080 so giving the fact that 3080 isn't that far from 3090 i will wait until 2021 with better disponibility and pricing.

Re: Memory in Graphics cards - better 2x3080 with each 10 GB or 1x3090 with 20 GB?

Posted: Sun Oct 11, 2020 4:45 pm
by Theo_Gottwald
Sure, I guess me too. But besides that.
Would you prefer A) 2x3080 or b) 1x3090 in case of ...?

Re: Memory in Graphics cards - better 2x3080 with each 10 GB or 1x3090 with 20 GB?

Posted: Sun Oct 11, 2020 9:52 pm
by Sharlybg
Theo_Gottwald wrote:
Sun Oct 11, 2020 4:45 pm
Sure, I guess me too. But besides that.
Would you prefer A) 2x3080 or b) 1x3090 in case of ...?
A) for sure with as much RAM as possible for out of core rendering. I will always prefere speed over anything execpt quality.

Re: Memory in Graphics cards - better 2x3080 with each 10 GB or 1x3090 with 20 GB?

Posted: Tue Oct 13, 2020 4:15 pm
by Theo_Gottwald
Hahaa ... I was tending for B) originally because "out of core" rendering is a lot slower. Do you have an idea how much slower it is?

Re: Memory in Graphics cards - better 2x3080 with each 10 GB or 1x3090 with 20 GB?

Posted: Tue Oct 13, 2020 4:20 pm
by Sharlybg
Theo_Gottwald wrote:
Tue Oct 13, 2020 4:15 pm
Hahaa ... I was tending for B) originally because "out of core" rendering is a lot slower. Do you have an idea how much slower it is?
this is becoming more and more irrelevant : viewtopic.php?f=5&t=840&start=1060

Image


From Dade himself
The slide is about CPU/SSD/etc. (any device attached to the PCIe bus) to GPU ram transfer rate. It can have a huge impact on some application.

In our case, it could highly increase the speed of "out of core" rendering.

Re: Memory in Graphics cards - better 2x3080 with each 10 GB or 1x3090 with 20 GB?

Posted: Wed Oct 14, 2020 5:47 am
by Theo_Gottwald
Definitely but:
1) Are there drivers?
2) Do you attach the SSD then to the Graphics card?
I doubt this will just work by inserting a graphics card into the system. At least there must be windows-drivers for that.
and finally:

On nvidia‘s graphic transfer rate from RAM to VRAM is 14 GB/s.
This is 32 times less than VRAM to GPU cache.

This is in the best case a 32x Penalty for "Out of core Rendering"!
Maybe we should try some scenes and then think again.

Re: Memory in Graphics cards - better 2x3080 with each 10 GB or 1x3090 with 20 GB?

Posted: Wed Oct 14, 2020 7:40 am
by Sharlybg
Theo_Gottwald wrote:
Wed Oct 14, 2020 5:47 am
Definitely but:
1) Are there drivers?
2) Do you attach the SSD then to the Graphics card?
I doubt this will just work by inserting a graphics card into the system. At least there must be windows-drivers for that.
and finally:

On nvidia‘s graphic transfer rate from RAM to VRAM is 14 GB/s.
This is 32 times less than VRAM to GPU cache.

This is in the best case a 32x Penalty for "Out of core Rendering"!
Maybe we should try some scenes and then think again.
Generally this is a question of time. And as Dade say it will greatly speed up Out of Core. Anyway in general i'm not a early adopter of new tech i prefer to let thing unwrap correctly before investement. As i say it is already question of Nvidia moving to 7nm. I'm Sure within 4months the story will be very different and much more clear.
Not only Ampere GPU are currently overpriced but also we don't know how AMD card are gonna stand along Them. We also don't Know how higher Ampere GPU will affecte Price ....

Re: Memory in Graphics cards - better 2x3080 with each 10 GB or 1x3090 with 20 GB?

Posted: Wed Oct 14, 2020 7:56 am
by Sharlybg
Watch this video :

https://youtu.be/zmbvUK93npo