Sakkura
Illustrious
Someone Somewhere :
Yes, but on many they are actually clocked differently. It's better on Haswell than on Sandy/Ivy, though.
There are small differences in the clock bands, but the real difference is in the TDP that determines where they'll sit within the very large range of clocks allowed. On the desktop CPUs, the base clock of all the iGPUs is either 200 MHz or 350 MHz. The max. turbo ranges from 1 GHz to 1.3 GHz (1.25 GHz is the highest among the non-R models). So all of them fall within reasonably similar ranges, but with a HUGE range from minimum to maximum clocks. So the TDP becomes crucial in determining actual performance.