Addendum:

> http://www.amiga-news.de/en/news/AN-2015-04-00032-EN.html :-)
> There seems to be L3 cache support even, as opposed to OS4.

No support for the P5's L3 cache in OS4 yet:

http://blog.a-eon.biz/blog/wp-content/uploads/2015/12/Video.jpg