Ms is saying that in some cases, for a 1080p/60fps title that they might be ROP bound during a time slice of the frame... That means that for all the other times it's not ROP bound, they could get away with even less ROPs... So yeah, double that number might be an overkill?
Not to mention the interesting point they made about ROP/Bandwidth ratio...
it might be overkill on xb1 yea, but on PS4? You can't just say it is based on one machine. If you could base it on just one machine let's look at other GPU's made by AMD they certainly don't find 32 ROP's overkill when you have a bandwidth of 176gb/s, in fact they use 32 ROP's with much less:
7850 32 ROP's 156gb/s
7870 32 ROP's 156gb/s
The only "evidence" they have is that somebody who works at Microsoft is saying in the XB1 they are only sometimes limited by ROP's.
Let's look at that Bandwidth example closer shall we?
8 bytes write 4 byte read for a total of 164gb/s which pretty much saturates their esram bandwidth, sounds a little odd to me.
Let's quote Goosens himself speaking about the esram:
http://www.eurogamer.net/articles/digitalfoundry-vs-the-xbox-one-architects
you don't get to spread out your bandwidth and so that's one of the reasons why in real testing you get 140-150GB/s
If you're only doing a read you're capped at 109GB/s, if you're only doing a write you're capped at 109GB/s
Now bear in mind this information comes from the same interview but in a different article. 164 is bigger than 140-150 In fact, i'd say he's a little off with his "pretty much" saturates the esram bandwidth, but wait, there's more.
What is the esram's maximum theoritcal bandwidth in write only? 109gb/s
What are his bandwidth numbers again? 164 with a split of 8:4 between write and read, which would be a total of: 109.333333gb/s write and 54.6666gb/s read what do you notice? It's higher than the 109gb/s maximum theoretical peak
Why Am I the only one doing this math, why isn't Richard Leadbetter? In one interview he has gone from 140-150 to suddenly using 164 and over the maximum theoretical write speed.
That is why this does not pass my smell test.