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I am waiting for the photography pros of YouTube to weigh in on that last bit but the Disney bit about 131GB of ram usage is intense. Surely a speedy disk can p

I am waiting for the photography pros of YouTube to weigh in on that last bit but the Disney bit about 131GB of ram usage is intense. Surely a speedy disk can page but likely not enough to make the 64GB of ram a bottleneck. Maybe things like optane or ssds will get so much quicker that we'll see a further fusion of io down to disks and one day we'll really have a chip that thinks all it's storage is ram/storage and doesn't really distinguish between it. Sure it's unlikely SSDs will get to 400GB/s in speed but if they could get to 10GB/s or more sustained that latency could be handled by smart software probably. I think for that cohort any future iMac Pro or Mac Pro with the future revisions of these chips will surely increase the ram to 128GB maybe even 256GB or more. I am super curious how Apple will tackle those folks who want to put 1TB of ram or more into their systems if they'll do an SOC with some ram plus extra slotted ram as another layer?

dragontamer 5y ago
> Sure it's unlikely SSDs will get to 400GB/s in speed but if they could get to 10GB/s or more sustained that latency could be handled by smart software probably. Yeah, I'm not part of the field, but the 3d guys always point to "Moana" to show off how much RAM they're using on their workstations. Especially since Disney has given away the Moana scene as a free-download, so anyone can analyze it. The 131GB is the animation data (ie: trees swaying in the wind). 93GBs are needed per frame (roughly). So the 131GB can be effectively paged, it takes several seconds (or much much longer) to render a single frame. So really, the data is over 220GBs needed for the whole scene. In practice, a computer would generate the wind and calculate the effects on the geometry. So the 131 GB animation data could very well be procedural and "not even stored". The 93GB "single frame" data however, is where all the rays are bouncing (!!!) and likely needs to be all in RAM. That's the thing: that water-wave over there will reflect your rays basically anywhere in the scene. Your rays are, in practice, bouncing around randomly in that 93GB of scene data. Someone managed to make an out-of-core GPU raytracer using 8GB of GPU-VRAM (they were using a very cheap GPU) to cache where the rays are going, but it still required keeping all 93GB of scene data in the CPU-RAM.

dragontamer 5y ago

> Sure it's unlikely SSDs will get to 400GB/s in speed but if they could get to 10GB/s or more sustained that latency could be handled by smart software probably. Yeah, I'm not part of the field, but the 3d guys always point to "Moana" to show off how much RAM they're using on their workstations. Especially since Disney has given away the Moana scene as a free-download, so anyone can analyze it. The 131GB is the animation data (ie: trees swaying in the wind). 93GBs are needed per frame (roughly). So the 131GB can be effectively paged, it takes several seconds (or much much longer) to render a single frame. So really, the data is over 220GBs needed for the whole scene. In practice, a computer would generate the wind and calculate the effects on the geometry. So the 131 GB animation data could very well be procedural and "not even stored". The 93GB "single frame" data however, is where all the rays are bouncing (!!!) and likely needs to be all in RAM. That's the thing: that water-wave over there will reflect your rays basically anywhere in the scene. Your rays are, in practice, bouncing around randomly in that 93GB of scene data. Someone managed to make an out-of-core GPU raytracer using 8GB of GPU-VRAM (they were using a very cheap GPU) to cache where the rays are going, but it still required keeping all 93GB of scene data in the CPU-RAM.