6600K undervolt+underclock = or > 6500T

[velizarw]

I am building a Tablet PC based on AsRock H110TM-ITX and currently I need to choose a CPU. My initial plan was to use a low power i5-6500T, but currently I have a very good offer for i5-6600K. Thing is that the first one is merely 35W compared to 91W for the K chip. I know for sure that stock 6600K will blow out of the water 6500T and I was wondering, would it be possible to downclock and undervolt the 6600K or use Windows/Throttlestop to make the 6600K chip reach a maximum of 35-50W TDP. If that is possible, how much of a performace loss will that result in - would it be still faster than 6500T? 

Other things that bother me: 1) The motherboard is non-Z and I have no idea if voltage and frequency control are possible. 2) If possible, would this downclock load the voltage regulators excessively and shorten the lifespan of mobo? 3) Is this even worth it or go with 6500T instead?

[Electronics Wizardy]

might as well get the 6600k, performance will be about the same.

 

Id probably not touch clock,  and just let it thermal or power throttle.