Hi
Lea56. There are plenty of threads here on the forum that discuss this situation and if you search I'm sure you'll find one that explains everything you're looking for.
Briefly, There's no setting for the scratch disk because PD uses the same drive and folder where your source media is located. The best performance will come from moving or copying the media to your fastest drive, whether that's internal or external. If you have an SSD disk, you can use that to measure the transfer speed of your other drives because they will not be able to keep up with the SSD and so the transfer speed you see is how fast that drive can read or write data.
If you have only one SSD, by all means load Windows and PD13 on it! "Editing" actually takes place in RAM but that's affected by how quickly PD can transfer the relevant sections of your clips there. Normally, newer HDDs can handle video editing without being a bottleneck, but if you use "shadow files" for working with HD/2k/4k clips, you'll really benefit from placing your clips on a folder on your SSD if you have enough room.
YouTube/optodata
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