Hardware performance for Photoshop (A large project)

[aiur4]

Well, I'm totally thrilled with a new 14/16 inch MBP and the performance blew my mind. I'm already happy with M1 without any issues in terms of performance which makes me feel not to buy M1 Pro/Max. But I really need to buy a higher end Mac because of Photoshop project. I know that M1 is totally enough or more than enough for Photoshop cause it works great and it really does. But the only concern is about a large project. This is why I waited for a higher end MBP or iMac.

Each project file size is between 10~30GB. Yes, it is huge. I tried it with Mac Pro 2013 and iMac Pro with 64GB of RAM but they were extremly slow to handle a such file. The memory was maxed out. Apple Silicon Mac with unified memory should be much faster but I'm still worrying about the RAM usage. Someone suggested to reduce the amount of RAM that Photshop can use but I dont think it will increase the performance. M1 with 16GB struggles so much with a huge file. The canvas size is 66X44 at 300 PPI. Zoom in and out is totally laggy and even iMac Pro suffered that. 

I'm waiting for Apple Silicon desktop with 64GB of RAM but do you think the struggle is more about the RAM size, CPU performance, or GPU performance? 

[jane-e]

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@aiur4 wrote on 18 October:

Tagging @Conrad_C , who may be best able to answer your question.

Jane

[Nancy OShea]

Each project file size is between 10~30GB. The canvas size is 66X44 at 300 PPI.

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Unfortunately, 66 x 44 means nothing without the parameters  -- pixels, inches, centimeters, columns...

If this is for print, do you really need 300 ppi?  I ask because a sign for a building is typically only 150 ppi or less. 

[aiur4]

I think it affects the quality especially for close up. This is more like fine art prints for exhibition and sale.

[Conrad_C]

The way memory and all those CPU and GPU cores interact in the newest Apple Silicon Macs is so different than traditional x86-based systems that it’s hard to say for sure what the best configuration is until we see more people doing tests with large files.

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@aiur4 wrote:

Each project file size is between 10~30GB. Yes, it is huge. I tried it with Mac Pro 2013 and iMac Pro with 64GB of RAM but they were extremly slow to handle a such file. The memory was maxed out.

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How was the memory maxed out? What was Memory Pressure showing in Activity Monitor; was it green, orange, or red? If it was orange or red, there was definitely not enough RAM; but if it was green, RAM was OK and the problem was somewhere else.

For CPU and GPU, you can see what Activity Monitor reports by choosing Window > CPU History and Window > GPU History, which are graphs over time. If a graph is always full, that is a bottleneck. If a graph is usually empty, either that is not a bottleneck or Photoshop isn't taking advantage of it.

You can test a large project on your M1 and see which of the areas are under the most strain — memory, GPU, or CPU. That could provide a clue as to how to configure a more powerful M1 for the same project. For example, if memory and CPU were not busy but GPU is, then that would suggest that a more powerful GPU might help.

But the answer might still not be straightforward, because the various features of Photoshop are not optimized evenly. Very generally, RAM is used to hold layers for editing, CPU is used to run calculations, and GPU accelerates some features, including view changes like panning and zooming. So it also depends on which features you use on the large project, and whether they match up well with the areas of Photoshop that are optimized for CPU cores and GPU acceleration.

[aiur4]

So I check both GPU and CPU usage and they didnt use too much of resoruces. The memory was maxed out but I limit it till 14GB of Unified memory. But it's still laggy and slow. I may need to test with M1 Pro/Max but I still think that Photoshop lacks better optimization for large files. 

[J453]

What is end product of files this huge?

[aiur4]

1. 66X44 inch size which is a huge project.

2. Many layers. Literally 50~70 layers.

Do you think 8 or 16 bit with ProRGB will matter for printing?

[Earth Oliver]

you don't need 16 bit for printing and don't use ProPhoto unless you know exactly what you're doing. 

[D Fosse]

First of all, you don't need 300 ppi for large prints. That's probably the most persistent myth in all of digital imaging. It has to do with viewing distance. 300 ppi is for books and magazines to be seen from less than arm's length. I've made wall-sized banners at 25 ppi, and they're razor sharp for the situation.

That said, though, for files of this size it's not about RAM. Forget about having "enough RAM", you never do no matter how much you have.

This is about the scratch disk. That's where the heavy lifting is! That's the bottleneck. You need a fast NVMe drive with at least 500 GB free space - but in this situation I'd go for a full TB.

These file sizes will be well handled by Photoshop as long as you have sufficient hardware resources, and in this case, that means bandwidth. They are well handled by x86 as it is, no problems that need solving.

[Nancy OShea]

Thank you @D Fosse.  I couldn't have stated it any better.

[D Fosse]

You're welcome 😉

[aiur4]

Well, I am working on a large project on a fast SSD and yet it is not different from working on HDD. I have 3 scratch SSD disks as back ups so that's not a problem. Still, it's laggy and slow to handle a large file. At this point, this is something that I can not understand why Photoshop is slow and laggy. 

[D Fosse]

Precisely how much scratch disk space do you have, and exactly how is it configured? Are these SSDs internal or external drives, SATA or NVMe? Personally I wouldn't attempt this with anything less than 1 TB on a fast internal drive (NVMe).

Generally, this isn't CPU-limited; it's I/O bandwidth-limited. It's about shifting huge amounts of data to and from disk. RAM is less important as long as there is a decent amount. Think of RAM as a fast access cache to the scratch disk's main memory.

I'm not saying there can't be other problems here, but in normal circumstances the scratch disk is the key to working with big files. Everything else is secondary.

[aiur4]

I have internal M.2 SSD with 1TB. But it didnt make any differences with HDD so I'm quite skeptical about it. 

[Earth Oliver]

Of course it's going to be laggy. No machine can really efficiently handle files that large. Well, no machines that any of us can afford.

[D Fosse]

A decent desktop system can deal with that. A laptop, not so much.

I don't think I've hit the 30 GB mark, but I've worked with 12 - 15 GB files without any serious problems. Of course, people will have different definitions of slow, and I'm not going to pretend it's as snappy as working with a "normal" image. But it's perfectly workable and Photoshop is moving steadily along.

Almost fifteen years ago, we worked on GB-sized files with CS3, all 32-bit, spinning drive systems. We would set up RAID0 arrays for the scratch disk to speed it up - but it was a steam engine compared to what we have today.

[Earth Oliver]

it's funny how almost every time someone complains about performance issues, they usually don't describe what it is that's slow...

[D Fosse]

Well, slow is relative and subjective and almost impossible to quantify.

My definition of "not slow" is that things are progressing in a more or less expected and predictable way, given the parameters. "Slow" is when progress stops and something is holding it up. Yeah, very subjective.

[aiur4]

I'm not sure how to tell this but it is slow. It takes 3~4 sec to zoom in unlike what I do with normal files which does not have any delay to view. Applying adjustments and brushing also shows a long delay.

I'm trying to tell you how to improve overall performance with a huge file. So far, CPU and GPU didnt improve well. 

[Earth Oliver]

if you want to work with files that large, your system and workflow needs to be highly optimized. I'm wondering, do you have auto-save active?

[Test Screen Name]

" I tried it with Mac Pro 2013 and iMac Pro with 64GB of RAM but they were extremly slow to handle a such file. The memory was maxed out. Apple Silicon Mac with unified memory should be much faster " 

I'm sorry, I don't follow that at all. If the memory is maxed out, then the DISK (SSD) is used instead.

The unified memory makes zero difference to this - except to mean you have less. The disk will still be needed.

Unified memory means there is less time moving info between the GPU and CPU. It doesn't give you more memory, or help you out when you need to use disk instead.

https://www.howtogeek.com/701804/how-unified-memory-speeds-up-apples-m1-arm-macs/

[aiur4]

I already tested with Mac Pro 2013 and iMac Pro with 64GB of RAM. Doesn't make any differences. 

[Earth Oliver]

that's because a 30GB file needs hundreds of GBs of scratch and unless you understand how to set up your file and Ps prefs correctly, you'll probably be making the issues worse than they need to be.

[aiur4]

I have at least 2 SSD so it's hard to understand it.