add scratch disks in Photoshop on widows PC

[moldred]

I have a few external Thumb drives, USB-2 drives, and an SDXC thing in the machine, but Photoshop doesn't recognize them. How can I fix that?

[Conrad_C]

To fix it, make sure a volume meets the Adobe requirements for Photoshop scratch disks (screen shot below).

A Photoshop scratch disk needs to be as close to the speed of RAM as possible, and one problem is that all of the devices you mentioned tend to have extremely slow read/write speeds. A Photoshop scratch disk works best if it’s large and fast. An example of a good scratch disk is a 1TB external SSD that can read/write at up to 1000MB/sec, connected over 10 gigabits/sec USB 3. Those are under $100 now. Some of the pricey thumb drives can be fast, but most of the cheap ones aren’t.

USB 2 can only reach about 0.5 gigabits/sec, and that’s why it’s a poor connection for a scratch disk. Compared to that, USB 3 is up to 20 times faster, and Thunderbolt 3 & 4 are 60 times faster.

Many SD cards read/write at speeds as slow as USB 2. Only the very expensive pro SD cards can consistently write at more than 100MB/sec.

[Ged_Traynor]

@moldred you really need to free up space on your c drive, with only 7.39GB of free space you're going to run into trouble on an OS level never mind Photoshop

[Conrad_C]

Excellent advice. For general OS use, 100GB free is a good goal. For Creative Cloud apps that need large cache/scratch files, the more space you can free beyond 100GB on your boot volume, the better.