Hi 3lj,
As for your item #1, the reason you you have twice as many "CPU Utilization" entries as you have Cores... your processor is likely Hyper-Threaded. That means that each core appears to to operating system as two logical processors each that can be scheduled separately.
If you would like to know more about HT, may I suggest the Wikipedia entry: https://en.wikipedia.org/wiki/Hyper-threading
As far as the memory clock, I would take a look in your BIOS and see if there are memory settings you can tweak to take advantage of the faster memory. It may be auto configuring to this lesser value.
FYI
-A