To me Haswell seems like an interesting generation. Is it the first Intel mobile generation to use a Fully Integrated Voltage Regulator (FIVR)? Subsequent generations didn't seem to use this technology anymore. I wonder if it contributed to extra heat generated? It does seem to correlate to the M4800 motherboard having a simpler CPU VRM design compared to the M4700.
2013 - ASUS ROG: Introduction To Fully Integrated Voltage Regulators (FIVR) On Maximus VI
(pdf) FIVR – Fully Integrated Voltage Regulators on 4th Generation Intel® Core™ SoCs