Z87 Extreme4 BCLK drop

[crz]

Hi all!
I have received recently Z87 Extreme4 for my new 4670k, and after some tests i was disappointed by bus speed value under full load (cpu-z and aida64 measured).
When idle, bclk frequency is around 100 (99.7-99.8).
But when i launch heavy tasks, bclk drops to 94-95 mhz, which makes processor running at 4200mhz with multiplier set to 44.
Firmware version is 2.30

I this a motherboard or software problem?

[crz]

Re: Z87 Extreme4 BCLK drop

Solution found!

Enabling Hyper-V role in Windows 8 Pro apparantly causes this bus speed reporting issue. Perhaps there's some sort of hardware abstraction layer going on under the covers when Hyper-V is enabled that causes CPU-Z and HWiNFO64 and a few other utilities to read a synthetic bus speed instead of the actual hardware registers.