I was testing a dual xeon system and I have noticed that during rendering in premiere only cores from CPU#0 were used.
Photoshop is also not using all cores!
Am I missing some settings? I am using CC.
What version of windows do you have on the machine?
You need one of the higher tier versions (pro i think) to be able to use the 2nd cpu.
It is Windows 8.1 Pro. Maya and other software use both CPUs