Memory requirements

rupaol

I recently came across a discussion regarding GPU memory vs RAM and if I remembered correctly, it was said that it was not only the GPU memory that limited the scene complexity to render in Iray but also RAM. 

Unfortunately, I can not find the discussion so instead I'll put out the question. What relation should there be (in general) between GPU and RAM memory? And is there a difference if the scene consists of a lot of geometry or large textures?

I have a system with 12 GB GPu and 32 GB RAM and sometimes get inconsistent drop outs when I try to render. Seems more affordable to increase RAM istead of GPU if it can improve the situation.

thd777

You have more than enough RAM for a 12GB card. You will not get any improvement by adding RAM. Only increasing GPU memory is going to help.

I just upgraded to a RTX4090 with 24Gb and that made a huge diffrence. My system has 128 Gb of RAM (I had a 11GB and 12GB card previously).

Ciao

TD

PerttiA

32GB's of RAM is not yet enough for DS not eating it up.

Depends on what one has in the scene, but I have run out of RAM with 32GB's and at the time I had only 8GB's of VRAM

superlativecg

I found a box full of old RAM sticks.  It brought back so many memories.

rupaol

Thanks for yor feedback. I have tried to do some tests and when I create a scene that really pushes the limits of the GPU 12 Gb memory (six Gen 8 characters and some environment), the ram usages also get very close to the avaliable space in the 32 Gb limit. From that simple test (using Windows Task manager and resource monitor) it seems useful to have additional memory. Especially if I want to run additional applications simultaneously. 64 Gb may be too much but I only ahve two memory slots so I guess I have to go with two 32Gb.

Or are there any other things to consider?

thd777

Hm, that sounds quite odd to me. Unless those six G8 characters and environments were heavily optimized with texture reduction, I doubt that you were using the GPU for that render. How did you establish that the GPU was operating? Did you check the log? GPUZ? 
TD

edit to add: no doubt this kind of scene will push your ram to the limit, but the GPU with 12 Gb is usually long out of the picture by that point. 

PerttiA

thd777 said:

Hm, that sounds quite odd to me. Unless those six G8 characters and environments were heavily optimized with texture reduction, I doubt that you were using the GPU for that render. How did you establish that the GPU was operating? Did you check the log? GPUZ? 
TD

edit to add: no doubt this kind of scene will push your ram to the limit, but the GPU with 12 Gb is usually long out of the picture by that point. 

It all depends on the assets used in the scene, one can not make estimates on RAM and VRAM usage based on the number of characters. One should know which hairs, which clothes and possible props have been used.
There has been countless of examples of items eating more than 10 times more RAM and VRAM than similar items on average, but there are also assets where the opposite is true.

rupaol

Yes, I'm positive that only GPU was used. Log reports and the speed of the render leaves no doubt.

I have learned to optimize the scenes getting just below what the GPU mcan manage but I have still no clue what additional RAM would benefit. Speed is not an issue, I am more looking for getting as much assets into the scene as possible without having to replace the GPU.

Maybe best way is just to purchase and try....

ArtisanS

Eh PerttiA, the first Mac came with 128 kB. And the OS ate so much of it that Opcode went out of memory when it was launched. And 2 month later a new model hit the market with 256 kB. How do I remember? A friend of mine was (and is) an early adapter. Ah painfull detail. Upgrading from the 128 to the 256 kB model should have been easy. It was easy, just buy a new one. And that was what my friend did. Now he was a musician and he needed it for work. And then the Atari 520 ST hit the market.

Greets (ah, yes I'm a MSCE indeed, so don't blame me for defending Bill ).

StratDragon

rupaol said:

Yes, I'm positive that only GPU was used. Log reports and the speed of the render leaves no doubt.

I have learned to optimize the scenes getting just below what the GPU mcan manage but I have still no clue what additional RAM would benefit. Speed is not an issue, I am more looking for getting as much assets into the scene as possible without having to replace the GPU.

Maybe best way is just to purchase and try....

 

optimization is underrated. it's amazing what you can do with a scene that brings your system to its knees with a little optimization, and it's cheaper than throwing more upgrades at your computer.