I have a DZ77RE-75K motherboard and after Updating to windows 10 my Core i7 doesn't boost or throttle, but is stuck at its top non boost frequency of 3.5GHz. I have the latest chipset driver installed from Intel, but it is rather old and doesn't say it supports Win 10. Am I SOL and need to fork over $150+ for a decent Asus board now?
Hhmmm, this could be something simple like the BIOS Settings are incorrect. I would make sure I have the latest BIOS installed, reset its BIOS configuration to factory defaults and then try booting into Windows again.
Of course, it could also be a lack of valid Windows 10 drivers. Officially, Intel does not support Windows 10 on any of the Desktop board products. Further, because Intel has exited from the motherboard manufacturing business, they likely never will. There are alternate sources for version of the Intel drivers (and things like the INF Update package) that will still support these boards with Windows 10. Intel has not (and will not) validate these newer drivers on these boards, so you are on your own to try them. See my responses in this other, similar thread: /thread/78703 DH87MC Windows 10 drivers?...
Hope this helps!