Nexus7 on 03 November 2016
Well for one we don't even know if the Switch will hit 750 Gflops even in FP32. I doubt Nintendo is going to aim for 15 - 20 watts for this device which is needed to hit that number. I'm guessing they will lower the clock rate to improve battery life. Also, even in docked form I feel the form factor is too small to handle the 15 - 20 watts TDP.
Lastly, that SoC will be heavily bottlenecked with its 3GB's of LPDDR4 Ram and 25 - 50GB/s of memory bandwdith, so even it if did hit 750 Gflops it wouldn't be performing at its full potential.
