Again, as others have pointed out in this thread, it is not that crystal clear that Ryzen has the energy efficiency metric won. Yes, the 1700 uses low power, but it also is clocked low. So the "efficiency", i.e. work performed per amount of energy consumed is not nearly as spectacular. And performance does matter. If "energy efficiency is all that matters" then why arent we using all atom in macbooks? Obviously, Apple, as any other manufacturer choses a *balance* between power and efficiency.
Not that much lower but the efficiency is pretty apparent when looking at power usage per core (90w for 3.9GHz 8c, versus 90w 4.3GHz 4c). Sure Ryzen isn't as fast or quick as a i7, but it's per core efficiency shouldn't be questioned.
There are a bunch of fallacies.
1. That Ryzen is a step back. In the purest sense it is SL and KBL and even now Coffee lake are chips capable of clocking faster and overall the cores offer a higher IPC. But a lot off the "step back" is in the clock speed. If they even out Ryzen offers a lot more "resources" for the workload.
2. The reason they would equal out is that every single Apple product right now is severely thermally limited. This isn't about what Desktop fully unlocked and power sucking parts are better. They use much more power restrictive models and the two are probably closer in clock speeds per watt as the power gets more restrictive.
3. Tons of Apple products rely on iGPU. For those systems Apple has been sacrificing a lot on the CPU to maintain usable graphics and as many have contended have force Intel into at least evaluating using another manufacturer's GPU on an MCM module. That will probably not see the light of day if it even existed.
4. With AMD's APU all of a sudden you get high 2GHz low 3GHz 4c8t with as good if not better than iris level graphics. This would be a big win for several of their product lines.
5. Apple could buy AMD. They are probably valued at enough to make a strong push to purchase Intel but they aren't that much larger than Intel and Intel also is a ridiculously high margin company. Between the physical value of the company, the revenue, the profit, and the stock value of the company it would take Apple almost a Trillion dollars to purchase them. Losing Apple would be a big hit, but not crippling, and the biggest reason to play ball with Apple wouldn't even be in lost revenue but because AMD gaining Apple would give AMD a platform to financially solvent for a long time. If Intel is worried about AMD as they climb out of the pit they were in, what would an AMD swimming in money look like.
6. On the same end Apple makes shrewd moves to basically pull a Walmart in terms of pricing bringing their suppliers within a brink of selling at cost by the sheer volume they at and anything they can't do that to they basically absorb and build up a company to do it for them. They don't have nearly the same negotiating power with Intel as they would with AMD.
7. In the end any AMD even with a long running relationship with them on GPU's is probably a tactic to get better pricing from Intel. Intel is still the better part overall. With better history off competitive. They are already able to influence Intel's design decisions. This is something that even Dell and HP have struggled with in the past. There is little reason to make a switch if you don't have to. All Intel has to do is play ball and they keep the contract.