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With Vega running into a wall in terms of clocks due to power, I can't see Navi solving this issue on 7nm to the extent AMD needs to achieve that level of performance at 150watts. Navi will have a moderate amount of shaders because of the 256 bit bus and a moderate amount of ROPs to achieve mainstream pricing. That would means it would needs high clocks to make up the rest and this is where power becomes an issue. 7nm is not going to be the magic bullet considering where Polaris 30 currently is at and from what we have already seen with Vega 20 at 7nm.
From what we have seen already, Vega 20 7nm has performance approximately at Vega 64 + 15% considering the 1800mhz clocks and it does this at 300watts(and this is the main reason Vega 7nm is not coming to consumers as it performs along the lines of rtx 2070 but at much greater cost to AMD).
...Because past hawaii, the rumor about performance that has been the most true has been typically the most pessimistic and worse case scenario. This includes the r9 285 through Vega. That is, they are worse than the competition with significantly worse power draw. If you look at AdoredTV expectations of performance for AMD cards, the only one that was correct the one where Vega was a disappointment, which should have been obvious considering the silence from AMD officially while Pascal was cranking out record sales. The Shanghai GPU team has just been a disappointment so far compared to the Markham team.
AMD is barely able to catch Maxwell even today in terms of performance per watt.
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