Not when its boosting performance by upto 25% though which is the difference between Guru3D and Hardwarecanucks results. If you look back to when it was implemented,the variation was far less(more like 5% to 10%),and that is what I see with "all cores" Turbo on my IB rig,Haswell rig and a mates SKL Core i7 one.
The thing is in this very thread people said a cheaper motherboard and a more expensive one would be no different apart from bling,but apparently it does look like the better ones might be actually boost performance a good amount too.
What I am more interested to see is if the Core i5 8400 and Core i7 8700 has similar variation,since that has potential to really help performance over a cheaper motherboard. I don't care about 5% or 10% but 20% would be quite significant.
If anything I see more noise about the Core i5 8400 and Core i7 8700 now since the K series SKUs are hard to get hold off,and the Core i7 8700 has Turbo upto 4.6GHZ which is very close to the Core i7 8700k,but a very low base clockspeed of 3.2GHZ or thereabouts.
It makes me wonder whether a Core i7 8700 non-K in a motherboard with aggressive MCE will outperform a Core i7 8700K on a cheaper board with less agressive MCE??
Having said that I see you have an overclocked Xeon E3 on a C232 chipset. Sneaky!!
I remember being one of the first UK posters to talk about the Xeon E3 series - I miss that series!!