you can have the installation on one drive and the whole data/log/configuration on another. But you cannot put only some of the data-patch-folders elsewhere.
In many cases, PRTG does not benefit a lot from using an SSD, neither for the installation folder, nor of the data folder. This is because PRTG was conceived at a time where there were no SSDs. Because harddisks are still much more affordable, we also try to maintain the PRTG architecture that an SSD does not become necessary.
It is however important in order to get good performance, to use a drive locally in the server (no network-attached solution.)
An SSD of course does not hurt, but with a typical PRTG setup in mind, our tests show that performance gains are usually not very big. In some cases, reports are generated faster, but unless you create a lot of large reports very often, the practical gain is not that big. Most of the times, reports run in the background as a scheduled task in PRTG, so the performance does not play a very large roll.