by kraada » Tue Jun 25, 2013 6:49 pm
An SSD is a solid state disk drive - the really short version is that it's a much, much faster hard drive (it doesn't have spinning platters, it's not mechanical in the same way, as it's more like a USB flash drive in a hard drive form factor and size). Reading and writing data to your database is one of the big bottlenecks for PT4 and so being able to do that more quickly is important. It's also a particularly nice benefit to have your OS on such a drive as basically everything else loads faster as well.
Regarding RAM: PostgreSQL can use any amount (so long as you have a 64 bit version installed); it depends on the size of your database whether you would need it or not (once the entire database fits in RAM, you wouldn't really need more). But obviously if there's less, then PostgreSQL will make do.
The reason the CPU speed is next on my list rather than RAM isn't to say RAM isn't important it's to say a faster CPU will help a little more, especially for processor intensive operations like large imports or NoteTracker processing hands.