Photoshop CS6 scratch disk on hard drive or SSD?

Question

I've purchased a Windows 7 PC with 16 MB RAM, 2 terabytes and a 250 GB SSD. I'm going to load Photoshop on the SSD and the OS on the hard drive. Where should the scratch disk go?

Answer 1

It's a bit tough to answer, as you have not described how you'll be using your system overall.  Are you going to be doing almost exclusively Photoshop work with it or are you looking for good all-around performance?
What brand and model SSD is it that you have, specifically?  Generally speaking, if it's a modern model SSD with wear-leveling features in its internal controller, and with the other givens you mentioned, you will probably want to use the SSD for scratch, as SSD throughput is very high (hundreds of megabytes per second).  With SSD throughput levels, when Photoshop starts using its scratch space heavily the performance hit is much less severe than with an HDD.  There is also not nearly as much concern with an SSD about dedicating the drive to the task, as even if there are other activities on the drive the near-zero latency means that SSD supports multitasking much better.
However, if you feel you'll never exceed 250GB for OS and applications (i.e., you're going to keep a relatively simple system), using the SSD for operating system and apps alike might be a better approach.  In that case there won't be enough space also for Photoshop scratch.
Just keep in mind, when planning your "this goes here, that goes there" distribution that Windows and its apps are really most comfortable with EVERYTHING running on drive C:.  That's not to say it's a necessity, just that things tend to work more smoothly in that setup.  Given that, you might actually consider getting a second SSD and making a RAID 0 array for drive C: with plenty of space available.  That's the approach I took (in my case with four SSDs).
-Noel