Not sure I can help on your lazy processor, but we do have a Premiere Pro BenchMark PPBM that will test the hardware and setup with Premiere itself. Right now you might will not be able the register on the site as my partner is recovering from a problem. But you can download the benchmark and run it and post the Output.csv file results here.
Thank you for making the time. I followed your instructions, great little piece of software. Here is a screen shot when I ran my test...
As you can see even on your test, only 1 CPU is being used by Premiere. The results from the benchmark were uploaded under the computer name RedShredder (I use it to edit and render Red Dragon 6k footage).
The results from you output file are as follows: "32","44","8","206",Premiere Version:, 184.108.40.206
I couldn't register at the site but will try again later.
My concern is that no matter what I do Premiere and the entire Creative Cloud ONLY see ONE CPU on my Dual Xeon system. Sometimes it will run on the other one and you can force it to by changing the processor affinity selection but no matter what, even if you click all cores on both CPUs it will still pick one and just run on that processor.
Any help would be appreciated,
Tomorrow I will reply
I sent you a direct email when I did not find this thread
I know the problem. It's definitely a software issue. In windows, their are processor groups that are limited to 36 cores. With hyper threading on, your two processors go exactly over twice that amount (or 72 logical cores) forcing windows to create two processing groups. If you disable hyper threading, Adobe will recognize all the cores and gain about a 30% performance increase. Why not a 50% increase you my ask? Because of another software limitation that is unknown.
More background here: Tweakers Page - Single or Dual CPU
Processor Groups are limited to 64 cores. As soon as you have more than 64 cores, the processor group limitation of Adobe software rears its ugly head and effectively shuts down either one CPU or turns off hyper threading.