Just to confirm, you have a local SSD and the temporary and results files are located there? Yes, I don't believe there's any problem with having them both in the same place.
16 GB SOLRAM should be plenty for that model size - like I said, 8192 (8 GB) works fine for most models, but there's no harm in going larger unless you actually start running out of RAM during the solve.
To find your CPU model, go to My Computer -> Properties, or press Win+Pause|Break. Mine, for example, is a Xeon E5-1630 v3:
There are a variety of benchmarks that compare single-thread performance (and they don't all agree on which CPUs are faster), but this one has the advantage of listing scores for the majority of CPUs:
PassMark CPU Benchmarks - Single Thread Performance
As to why a task can, or can't, be made parallel, my knowledge of programming and maths isn't sufficient to begin that discussion!