Is it really that bad though? In geekbench, the 4.5 W i7-7Y75 more or less matches A11 in single-threaded tests, and it's still a 14 nm chip. Obviously it loses in multi-threaded because of A11's 4 companion cores.
This is still a great achievement by apple though. No question about that.
This is a fantastic achievement. If Intel had these cores, they'd be parading around the country touting its benefits.
Since A11 isn't out for comprehensive benchmarking, let's look at A10X. The A10X is a valid alternative because the performance is essentially same as the A11.
-While the Single Core performance may be comparable between A10X and Core M, multi-threading is faster on the A10X and A11.
-A10X goes into a Tablet that weights 1lb and 6mm thick, and has no thermal issues. Their A-series chips also have no issues with throttling from top performance. With Core M ones, ever since Broadwell in 2015, we have come to expect a rather significant variation in performance depending on thermal design, set TDP, and code being run. Often, companies have to use the cTDPup 7W to lessen the performance loss by going Core M.
-Battery life based on Apple chips are 40-60% better than Core M ones. The former is roughly comparable with Atom-based devices while the latter is essentially equal to 15W rated Core chips - TDP does not matter for battery life because modern chips have advanced power management. Core is substantially behind.
-A10X/A11's GPU performance is on the class of expensive eDRAM-equipped Iris parts. The Iris parts are so expensive no one uses them outside of super expensive custom configs or absolute top of the line devices. Also, it does not exist at 5W.
-Technically, A11 Bionic is absolutely awesome. No one outside of Apple has achieved true asynchronous multi-processing. Many companies have come and went trying to achieve what they have done with A11. It's really hard to take advantage of the 4 small cores and 2 big cores in A11 to work with synergy. The controller in the A11 seamlessly manages the transition between the two and essentially acts like a better version of Intel's Hyperthreading. The small cores also allow low-usage power consumption to be better as well, a benefit that Hyperthreading lacks.
Apple achieves the best of both worlds - Atom-like thermals and battery life, along with Core like performance. They even top that by doing it better than Core on graphics. Their multi-threading implementation with 4 small cores are really awesome too. Top-notch in all metrics.