SSD vs RAM buying decision for 14" MBP

[project_2501]

For a 14" MBP M1 Pro I am comparing the following options:

• 32GB RAM and 1TB SSD
• 16GB RAM and 2TB SSD

Normally ram and ssd capacity would be separate considerations but with the M1 testing so far it seems Apple has successfully balanced the use of fast SSDs as swap to extend memory.

My workloads include video recording and editing, data science development, 3d rendering eg blender, 2d design eg affinity photo design. My setup includes an external 4K display. The reason for upgrading from my 2015 MBP 15" is that it is physically degrading and has had more frequent repairs, and it overheats with noisy fan when doing some of these tasks (fan noise ruins recording), video exports can take 2 hours. An external DSLR HDMI-to-USB causes crazy heat and fans noise.

Going from 512GB to 1TB SSD has been shown to double write performance which obviously helps performance when swapping due to memory pressure.

I'm not going for the Max as the performance to cost isn't worth it yet, and it isn't a good fir thermally for the 14" form factor which I prefer for portability (the 2015 MBP 15" is dragged around)

What are your thoughts?

 

[bsamcash]

You can upgrade storage externally. You can never upgrade RAM. Go for RAM.

 

[wilberforce]

I have a 14" MBP with 16GB RAM and 512GB SSD (I am pretty happy with this, except should have got 1TB).

My thoughts: I would get 32GB RAM and 1TB SSD. Reason: After my testing, although 16GB works fine, there are some potential benefits to 32GB, and your workload appears more intensive than most. The other reason is that for video work you are going to eventually need external drive(s) anyway.

On my iMac I have a 2TB SSD, and really like the extra breathing room, but I still have about 20TB on external drives.

btw, 512GB to 1TB does not double write performance, not in this case. The SSDs are so fast, that just pick the size you want/afford.

MBP 2021 - SSD Speed Comparison - Please Contribute!

From some of the YouTube reviews, it looks like there are SSD chip configuration differences between the 14" and 16" models and significant speed differences across SSD sizes. Can I please get everyone's help to run Blackmagic speed tests - only takes 2 minutes. Please use 5GB stress file size...

forums.macrumors.com

Of course you are going to get people saying get both. But it's not their money.

Another thought: I don't know if you are planning on the 8/14-core or the 10/16-core. The video encoders are identical. I'm not sure the $300 extra is worth it. So you actually have a three-way decision: #cores vs RAM vs SSD. I think I might put #cores as third in priority, but would research carefully the speed advantages for your particular apps. For H.264 exports there is apparently no advantage, and Blender only a tiny advantage:

 

[project_2501]

Thanks @wilberforce - very useful reply.

The cores point is interesting. Multithreaded apps will take advantage of them but currently not many apps are optimised for more than 1,2,4 threads because that's what previous CPUs had. This will change I expect.

Also - do you know if more cores means more numerical acceleration (AMX units) which will be taken advantage of by Python's numerical libraries, currently undergoing development ... or does a single SOC have just 2 AMX units ...

The GPU cores can also be used for maths but I'd need to go to Max for those and currently they're not a good fit for the 14"

 

[wilberforce]

Thanks @wilberforce - very useful reply.

The cores point is interesting. Multithreaded apps will take advantage of them but currently not many apps are optimised for more than 1,2,4 threads because that's what previous CPUs had. This will change I expect.

Also - do you know if more cores means more numerical acceleration (AMX units) which will be taken advantage of by Python's numerical libraries, currently undergoing development ... or does a single SOC have just 2 AMX units ...

The GPU cores can also be used for maths but I'd need to go to Max for those and currently they're not a good fit for the 14"

I don’t know the answers to your questions, but hope you get input from others

 

[SpotOnT]

That is a hard choice. Intuitively, the logic would be get 32 GB of Ram, since you can always expand storage with something like a Samsung T5. Recently though, I have been reading some reviews arguing that the memory swap in the M1 devices are so fast, you are better off going with a larger SSD for the same price. The argument being that 1) there is almost no performance hit with having less RAM, 2) a larger SSD has a longer lifespan 3) a SSD can be used for both RAM and non-volatile storage 4) you won't often hit the RAM ceiling anyway. So basically the larger SSD gives you more flexibility with almost no performance hit - so you get more bang for your buck.

Personally, my gut instinct would still be to go with the 32GB of RAM though. More RAM is better for long term use, when software gets even more bloated. More RAM should mean less swap to the SSD, so less stress on the SSD. And again, you can always expand your storage pretty easily with an external drive. Not sure if that attitude is just me being stuck in my ways, so to speak, but that is what I would go with.

As for the 8 vs 10 core suggestion, that is certainly another thing to consider. I would assume for math calculations, having the extra 2 performance cores would be helpful though. That being said, the Matrix Coprocessor is per SOC, not per core (as far as I understand it, they are seperate units in the SOC, like the Neural Engine).

 

[wilberforce]

Although I find that 16GB works perfectly fine, this is what made me think there may be some benefit to 32GB. Lightroom (which is particularly greedy for RAM when working on large files) sucks up about half the available shared RAM for its GPU acceleration (which does not happen on an Intel machine with separate VRAM). This is running only Lightroom, no other concurrent apps. Of course, YMMV for other apps

For very large files (such as stitched panoramas, or super-resolution files), Lightroom will take over 20GB RAM, with over 10GB swap. It uses about half that amount of RAM on my Intel iMac (which has 8GB separate VRAM) for the same task

 

[SpotOnT]

Yes, I absolutely agree, 16 GB just feels too limited to me.

Of course, the counter argument people will tell me, is that nearly all the benchmarking shows no perfomance loss, thanks to the fast memory swap. So the high memory pressure with 16 GB isn't really a concern anymore with the new unified architecture.

 

[wilberforce]

Yes, I absolutely agree, 16 GB just feels too limited to me.

Of course, the counter argument people will tell me, is that nearly all the benchmarking shows no perfomance loss, thanks to the fast memory swap. So the high memory pressure with 16 GB isn't really a concern anymore with the new unified architecture.

I agree, I don't seem to have performance issues with 16GB. Editing very large files in Lightroom can get laggy, but so is my 2020 iMac with 32GB. However, I can see some potential benefit of having 32GB. This "maybe" benefit is not worth $400 to me, but might be to others. (If it was $200 I think it would be a good choice.) Whether going from 1TB to 2TB is worth $400 is also debatable and person-dependent. External SSD storage is cheaper, and you may need it anyway. Again, if it were $200 extra, I think it would be a good choice.