Processor/computer specs needed for large format, printed art

72 x 72 in at 300 ppi is 21600 x 21600 pixels.

That's a huge file by any measure, especially with a number of layers. Don't even think about doing that on a laptop, whatever the logo on the lid. It will never fly. That requires a workstation, and a well-speced one at that.

What most people don't think about regarding laptops is temperature. To avoid melting everything is throttled down, no matter the nominal specs. It may be impressive on paper, but in real life any decent workstation will run rings around any laptop.

As for the actual specs, there are three things that matter: scratch disk, scratch disk and scratch disk. It's where it all begins and ends. Your scratch disk needs to be fast, preferably NVMe, and it needs to have a lot of free space. For something like this, you'll need a dedicated disk of at least 500GB with nothing else on it. Personally I'd go for 1TB.

With documents of that size, the base model of the 2019 16" MacBook Pro is a good place to start, but with a few adjustments:

• CPU: While you can pay for a CPU upgrade, 2.3 to 2.6GHz is only a 13% difference for 16% more money. So this is not the most important change. 6 cores is probably enough because Photoshop is unlikely to make full use of 8 cores for very much. But it won’t hurt to upgrade the CPU if you have the money.
• RAM: 32GB minimum for documents of that size; 16GB RAM is probably not enough. If you have the money, the maximum 64GB RAM upgrade would probably be reasonable.
• Graphics: The base GPU is probably good enough. Maybe upgrade it if you will be running multiple 4K+ displays connected to the Mac.
• Storage: This is the big one a lot of people might miss. When you edit documents of that size, Photoshop wants to create a huge temporary scratch file to cache anything that won't fit in RAM. (It will be released when you quit Photoshop.) This is controlled in Photoshop by the Scratch Disks setting in Preferences. By default, Photoshop will use the system drive. If your computer’s internal storage is almost full,  you will not be able to work on a large document very long before the computer runs out of storage space and Photoshop refuses to go any further. To be able to edit documents of that size, it would be a good idea to always keep at least half a gigabyte of free space on your designated scratch disk, on the fastest type of storage you can afford. (If you put the scratch file on a slow hard drive, that will slow down Photoshop.)

There are two ways to solve the scratch disk problem. You could simply order a MacBook Pro with 1TB or more of internal storage. However, those upgrades are expensive because Mac laptops use the fastest available storage. A cheaper option, which I did, is to buy an external solid state drive (SSD) with a USB 3 port, plug it into a USB-C port on the Mac, leave it empty, and assign it in Photoshop as the primary scratch disk.

I should add that I am not sure if that will guarantee responsiveness when drawing. Stylus responsiveness can lag due to problems with the tablet driver software or Photoshop or both. I don’t usually draw in documents that large, my suggestions are based on working with large documents that are panoramas stitched from multiple photos.

Hello I'm Chamicara,

I got your problem Arnold.is your going to make a fluid gradient cover art on a higher bit range.for that situation you need more processing power and more RAM capacity.Macbook is the best but is your going to change your Mac for this event take a look out for these specs.

1.A higher Resolution Display with refresh rates 50.00Hz to 60.00Hz (because you're going to work with pixels per inch)

2.Need more Processing Power (Recommend 2.3GHz to 2.6GHz and need more L3 cache memory) 

3.High Ram Memory 

4.Good Graphics (it's better GPU is more than 2GB storage)

According to these specs you can work with higher working range.I recommend Macbook 16 inch. If you're wish to jump for windows PC please contact me 

Thank you

Chamicara Desilva