[sounds]

I wonder how heavily dI/dt events weighed on Intel in deciding to integrate the voltage regulator on-die in Haswell?

Tech Report [1] says the FIVR (Fully Integrated Voltage Regulator) is for:

• higher efficiency, lower voltage ripple

• cleaner power delivery [closer to the load, and controlled by Intel]

• very high frequency, to 140 MHz. This one seems relevant, reacting faster to dI/dt events

• the only apparent downside is that with more things in one package the thermal load is higher, but bear in mind haswell's very low overall power usage

[1] http://techreport.com/news/24802/leaked-slides-expose-haswel...