New Anthem AVM 70 and MRX 740 difference in processing

Ah, the old “I’m rubber you’re glue” defense.  Good one, in third grade.  I’ve denigrated no one — just merely pointed out inconsistencies and unfounded statements while trying to stop you from unnecessarily wasting $$$.  Guilty, but I can see how someone with insecurities and limited knowledge could interpret that as denigrating.  Learning is sometimes painful. 

I think the Anthem 520 would drive the rear speakers.  It should be easy enough to insert the 520 as a Preamp, then reattach the speakers to the 520 and do some comparisons.  If you have an Anthem Dealer that will let you borrow the MX 520 for a weekend that would be ideal.  Rears ideally should be for ambiance only in music.
If you can’t demo, then just get the 520 and if you find the power section inadequate for the rears just use the 520 as a preamp.  Most of the improvement will come from the RC, and you don’t need the processor for that as it is the same software in the AVR

@soix that wasn’t a defense. It was a response. Read the first sentence again.. If I had credible evidence to the answer then why do you suppose I would post this topic in the first place? 

I've researched the Anthem products and from what I've read, the Pre-Pro has a better power supply and much better DAC's than the receivers.
I'm sure you could tell a difference, especially in 2-ch listening.  
But since you have a dedicated 2-ch system, I would probably just go with the receiver and be done with it.

Also, some manufacturers (I believe) use the same internals in their receivers as they do their processors.

That’s a statement, not a question.  It’s negative, ignorant, and accusatory.  A question would be: “Do some manufacturers use the same parts in the prepro sections of their AVRs in their AVPs?”  That’s a worthwhile and legitimate question while yours is just a completely uninformed, pigheaded statement.  See the difference?