My company owns two machines at the moment, on with v6r1 and a v7r1.
I do not know what kind of hardware runs either yet.
If you have access to a command line on both of those, you can try
Resource Type-model Status Text
CEC01 8286-41A Operational Main Card Enclosure
8286-41A is a Power 8. And can easily be found on the web. You can also
find out what they can be upgraded to at:
With some small print not available at that site. For example a bare
bones Power 6 can be upgraded to 7.2 but we had so many older cards and
enclosures that we had to swap out all of our Power 6's for Power 8's.