8x580
phoenix 238mhs, clay 243mhs
why such difference? long time ago mined eth and phoenix was faster.
With Phoenix it's need to use AMD memory tweak tool to set REF parameter. Claymore can do this by -rxboost option. Phoenix not.
Yet. Hope the developer will soon add this feature.
I hope too. But dev several years didn't add this feature... Hope slowly dies...
AMD mem tweak is there!
You just need to set the value to 30.
Even though it states 20 is default I've found 30 works better according to some researching about it.

Now they just need to release version 5.2 already so to fix the 4gb mining problem where the current release tells you those cards don't have enough vram to start mining. The warning is in yellow and is at the beginning of the process of detecting the cards you have installed in your rig.
And yes, program has been like this for the past month at the beginning of October.
It is a problem Phoenix Miner Devs!

Look:
https://bitcointalk.org/index.php?topic=5281830