Thank you very much for your answer.
C States are supposed to be idle states and should improve battery life, that was my guess, and they sure did no hurt when i did these (igpu issue was already there). I removed them anyway and also the acpi drops, CPU still idles at 800mhz.
But the issue with igpu remains, every system i ever did with intel GPU idles at 0mhz, even with older Ivy Bridge hd4000, so something is definitely wrong on that side.
I used the 7x40 bootpack on this forum to setup the machine, it all works good (except for hdmi at more than 1080p but that's not an issue here). I could try to raise the stolen memory to 128mb to see if that changes anything.
things i tried :
remove the connector patches under devices (not the stolen memory patches)
disable the dock patch in kexts to patch
disable all the C states checkboxes (actually made no difference in idle pkg consumption)
gonna remove PNOT (i got that in the bootpack..)