Yes, the IGP on the Core iX processors still consumers power even with a discrete GPU present. The IGP is part of the memory controller, so it's not possible to shut the IGP off.
actually i heard if you have a gpu connected in the P55, it disables the IGP.
Not to sure about this, but it was suposed to be one of the things sandy bridge migrated from that platform.
I'm pretty sure this is only possible with the nVidia chipsets.
no sandy bridge as shown by anand allows you to switch on the fly from igp to dedicated to conserve power.
Guys i really dont understand the whole point in being nit picky about every last voltage.
Honestly the difference between a full on power saving system and a medium level desktop is small.
Were talking about small voltages on stock.
Lets think about it... CPU TDP's on average is around 65-90W.
The LV TDP's start @ 40-65W
The ULV's go lower to 15-45W.
In idle, im sure its even smaller then that.
On load, it wouldnt be something breaker breaking.
On a Laptop i can see this being important.
On a Desktop, not unless your grid is on a solar array.