Will I need an external scratch disk?

[danqi]

I am doing photo and video editing as well as some 3d (Blender) and will be updating from a 2010 Mac Pro.

In the Mac Pro I use a dedicated 1TB SATA SSD as a scratch disk for caches and such. I was taught that it's always best to keep a scratch disk that is physically separate from the system drive and the media drive for optimal performance.

Now that I am planning how to upgrade to a Mac Studio I am wondering: Is a scratch disk still necessary? Or is the internal SSD so fast that it can handle the system and this job at the same time?

 

[bsbeamer]

For a production-ready machine and setup, I'd recommend using the internal shipped storage for OS, system files and all applications. I would not set scratch drives to that internal drive. Personally would recommend an NVMe blade in 40Gbps TB3 housing as scratch for best speeds, but getting a multi-bay SATA array and setting one of those drives might be fine for your needs. If you're using Adobe, the scratch drive is almost necessary. This is basically the setup for most on iMac27" and those who have transitioned away from MP5,1.

 

[now i see it]

2-4 GB allocated to a scratch disk is more than photoshop will likely ever use unless you’re making billboards.
If you’ve got 64 GB in RAM, photoshop will ‘almost’ never need a scratch disk anyway.

 

[Moonlight]

I am doing photo and video editing as well as some 3d (Blender) and will be updating from a 2010 Mac Pro.

In the Mac Pro I use a dedicated 1TB SATA SSD as a scratch disk for caches and such. I was taught that it's always best to keep a scratch disk that is physically separate from the system drive and the media drive for optimal performance.

Now that I am planning how to upgrade to a Mac Studio I am wondering: Is a scratch disk still necessary? Or is the internal SSD so fast that it can handle the system and this job at the same time?

You will be fine using the internal SSD as scratch disk. I used about 300-500GB of scratch disk and have been using my Mac trash can internal drive like this for 9 years with no issues. The internal drive is much faster than any external enclosure that it makes up for the antiquated notion that a scratch disk needs to be separate from the OS.

 

[bsbeamer]

Everyone's needs are different and so are needs of photo vs. video. Personally find the scratch cache on a non-system drive is faster performing and also slightly easier to manage, especially with video. The indexing and database of Adobe video apps can easily reach several hundred GBs if you're not keeping an eye and/or cleaning old versions out.

If you're splurging on an 4TB or 8TB internal, then this probably isn't a huge concern. Most I know are sticking with (or upgrading to) 1TB internal system drive and relying on external SSDs for everything else.

Regardless of the internal or external drive, you really want to avoid keeping at 80%+ capacity for extended periods of time. They need headroom to operate most efficiently. Apps like DriveDx can help monitor that and alert if approaching the level and monitor a bunch of other stuff.