Gaming reviews have NOTHING to do with mining usage.
Try looking at the various build-up reviews for the Vega FOR MONERO MINING USAGE.

For a specific related example, most of the reviews I have seen put "high load" power usage of a GTX 1070 ti in the 180-220 watt range - yet the MOST EFFICIENT mining point for those cards is 106 watts give or take a couple, and even folks that "push" them for higher hashrate rarely go higher than 145-150 range because the gains above that are TINY compared to the increase in power usage (my specific 1070 ti mining cards are currently set to 105 watts to keep total system draw under 6 amps on the system they are in).

Also, the Vega 64 pulls a lot more power IN GAMING USAGE than the 56 does, the 56 was deliberately designed by AMD to have a much lower TDP limit

 YOU need to check your ASSUMPTIONS, that's where you are messing up.

 Floating Point operations are 100% WORTHLESS for cryptocoin usage, which is 100% INTEGER operations.
 Another BAD ASSUMPTION you make, not a mistake on MY part.
 Would you also care to explain how "LTE16x" cell phone interface helps mining? Just for ONE example of the "not useful stuff for mining" on a Snapdragon 835.
 
 My "under 300 watt" measurement was made AT THE WALL on a Brand power meter while the system was actively hashing at 1950+ hash on Monero mining - and that was on a system that is NOT "power optimised" well, as I've never figured out how to get bloody Wattman to do a lot of the stuff I can do routinely in Afterburner like UNDERVOLT (Vega 56 cards LOVE to be undervolted, they tend to clock HIGHER with some undervolt as it lets them stay below the TDP easier). It is running a severely overkill Gold-rated power supply (Seasonic X-850) because that's what I had available when I put the system together, but the system is based on a FM2 motherboard with am AMD A10-7890k (which is NOT a low power APU) with the iGPU running the graphics for Win10, an HGST 3TB hd (system is also doing BURST mining) so the actual power draw of the SYSTEM as a whole would probably be about 275 watts (That model of PS usually pulls about 92% efficiency in the 30-50% load range).
 220 watts draw for the GPU is a PESSIMISTIC estimate, as I'm pretty sure the rest of the system is pulling 80-100 watts total NOT 50-60.

 Presuming an optimistic 2 watts, can a Snapdragon manage 20 hash on Monero?
 8 cores at 2 Ghz (ballpark average, I saw the "big/little" core split) in theory should manage more, but how much CACHE do they have on them - Monero wants ballpark 2 MB of CPU CACHE MEMORY per thread to run efficiently (and I can't find a spec anywhere that shows the amount of CPU cache on a Snapdragon).

 Then figure in the COST of the things - even *IF* they can mine efficiently, is it worth the COST of the things for whatever hashrate they achieve?
 THAT is the primary reason pretty much any SoC setup gets ignored for mining - even if it IS efficient in hash/watt, the sheer COST makes the time to achieve ROI end up being measured in YEARS.