It might not be 10x but it's at least 3-5x more heat produced by these Core M chips than the iPad. I own both (core M macbook and iPad pro) and the iPad is both faster and runs cool, which is very unlike the macbook. The macbook can become intolerably hot from 30 minutes of light microsoft excel work.
Intel has figured out how to get these chips to turbo up to 5Ghz for momentary benchmarks but when they run actual applications it turns into a disaster. Go buy a 12" macbook and you will quickly find out why "fanless" and "intel" should never have been combined in the same product.
The 2015 Core M MacBook is not great. Its CPU and keyboard are why I didn't buy it. The CPU is at best mediocre and the keyboard is horrible. The 2017 Core m3 MacBook is quite a bit nicer however, on both counts, and it adds hardware 10-bit 4K HEVC decode too. It also does pretty well with sustained workloads. We actually tested this, by repeating Cinebench R15 for extended periods, over 30 minutes. Remember also this is not with a 4.5 W TDP, since Apple uses TDP-up.
"m3 (wood)" is my Core m3 on a pine table, and "m3 (granite)" is my Core m3 on a granite countertop, the latter helping to conduct heat away from the MacBook. You'll see that even with the insulating wood tabletop, the benchmark score only drops after 10 runs from 265 to 246, which is only a 7.2% drop. IMO, that's pretty decent for a fanless laptop.
On the flip side, I couldn't easily get through a couple of HEVC videos I had that I was trying to play back using software playback on my iPhone 7 Plus. It'd play perfectly fine for about 10-15 minutes, and then stutter like mad. I'd let the phone cool for 5 minutes, and then it'd play fine again, so obviously it was overheating. The good news is nowadays hardware HEVC decoding should be available to third party players, but the point is it didn't do great when forced to run for extended periods under sustained load. These chips are great, but they're not magic.
Fortunately, it probably does better in a 13" iPad Pro though, and the same can be said about A12 in a 13" MacBook.
BTW, what are the comparative die sizes? A11 on TSMC 10 nm is 88 mm2. A10X is 96 mm2 on 10 nm, and A10 is 125 mm2 on 16 nm. It will be interesting to see what's the size of A11X, and of course, A12 too.