More Ram or Upgrade NVME M.2 SSD HDD?

[Steve Bentley]

It used to be that AE would only use so much ram no matter how much you had. Given the history of AE I’ll bet that’s still the case. So I would suggest a faster drive and make your cache drive a drive that doesn’t have other software on it. Make sure too that the new fast drive is also on a fast bus – not all of them are.

I also find that more ram means more cache clearing problems. Try doing an intese render in AE , quit and then try compressing that rendered file in some other program. It can be terribly slow because the computer is still trying to deal with loaded ram and a massive paging file. Often it makes sense to just restart to clear the baffles. I find the more ram you have for AE the worse this “feature” gets.

And don’t be fooled by Graphics cards stats – AE only offloads to the card for very specific tasks, ones you may never use. For the most part its all CPU.

[Walter Soyka]

I’d go for RAM first, then get a bigger disk when you can afford it. 16GB is not a lot of RAM for working with 4K.

A little math: a single frame of 3840×2160 video at 8bpc requires 31.6 MB of RAM. You can only fit 517 of these frames in 16 GB or a little more than 17 seconds at 30fps — and that’s not leaving space for your operating system or any applications! Plus, there’s the fact that each frame actually consists of multiple layers (and sublayers as the image is rendered through the effects stack)… it goes fast.

You should only ever need to clean your cache if you have a glitchy frame appearing in preview or in render. Ae’s disk cache is self-pruning. It will throw out the old to make room for the new.

Ae can use as much RAM as you give it, since CS5. Anything that ends up in the disk cache starts in a RAM cache first, and only gets kicked out of RAM when Ae needs the RAM for something else.

As for the impact on render time — that really depends on what kind of work you’re doing.

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive   |   RenderBreak [blog]   |   Profile [LinkedIn]

[Steve Bentley]

Hey Walter, what i”m about to ask is not about correcting you but more to make sure I’m not missing something. Can you “show your work” on the math for the single frame of 4K? I’m not getting the number you get.

Also, doesn’t the memory for AE include an assumed alpha in the video buffer? so that would be one more channel (and more mb) to take into account.

And finally, while all the propaganda for AE says that it can use all the ram you give it since CS5, I’ve not found that to be the case in the real world. Sure it’s gotten better, but we work on some pretty heavy files here and with 128gb available i’ve never seen AE top out beyond 13gb, and its still not caching everything it could be if it could access more ram. Am I missing something here too? where I could be filling up the ram and being more efficient? And is this different between Mac and PC?

Or are the system tools lying to me about how and where the ram is filling. It would explain the long wait times when you purge the cache.

[Walter Soyka]

[Steve Bentley] ” Can you “show your work” on the math for the single frame of 4K? I’m not getting the number you get. Also, doesn’t the memory for AE include an assumed alpha in the video buffer? so that would be one more channel (and more mb) to take into account.”

Sure. Perhaps our numbers disagree because there are so many different definitions of 4K; I’m using UHD:

3840 pixels per line * 2160 lines = 8,294,400 pixels
8,294,400 pixels * 4 channels per pixel (RGBA) * 8 bits per channel = 265,420,800 bits
265,420,800 bits / 8 bits per byte = 33,177,600 bytes
33,177,600 bytes / 1024 bytes per KB = 32,400 KB
32,400 KB / 1024 KB per MB = 31.64063 MB

Ae also shows the RAM size of a frame in the comp settings window:

[Steve Bentley] “And finally, while all the propaganda for AE says that it can use all the ram you give it since CS5, I’ve not found that to be the case in the real world. Sure it’s gotten better, but we work on some pretty heavy files here and with 128gb available i’ve never seen AE top out beyond 13gb, and its still not caching everything it could be if it could access more ram. Am I missing something here too? where I could be filling up the ram and being more efficient? And is this different between Mac and PC? Or are the system tools lying to me about how and where the ram is filling. It would explain the long wait times when you purge the cache.”

RAM usage depends on a lot of factors, but I regularly see Ae going up to its allocation limit specified in preferences on our higher-RAM (64GB and up) systems.

Under Preferences > Memory, there’s an option for “RAM reserved for other applications.” Ae will use up to your total RAM minus RAM reserved for other apps. Note that this is shared memory among several Adobe apps — Ae, Pr, Pl, AME, Ps, Sg, and Au — so running multiple Adobe apps simultaneously will limit the actual subtotal that the Adobe memory manager will allocate to Ae. I generally leave a quarter of system RAM available to other applications.

How are you measuring memory use? It’s possible that you’re only seeing what’s used in the foreground process, and missing background processes and caches [link].

There’s some good background information on memory and storage in the docs:
https://helpx.adobe.com/after-effects/using/memory-storage1.html

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive   |   RenderBreak [blog]   |   Profile [LinkedIn]

[Steve Bentley]

Thanks for the reading material.
The math issue was a carbon based error on my end – forgot to divide by 1024 instead of 1000. So much for metric fixing all conversions.

I run pretty clean and with single apps but have never seen AE using much more than 13gb. (at least on the occassions i’ve checked when I thought it should be) Let me have a read and see if a setting is wrong somewhere.

Thanks