Overclocking the Intel Haswell-E series can be hit and miss. I was able to push the MSI X99A Gaming 9 ACK up to 4.4GHz at 1.335 vCore. The motherboard actually set the voltage slightly lower at 3.328. EIST, C-States, and turbo were all disabled in the BIOS. Power management settings were set to High Performance in the Windows 8.1 control panel.
Gaming Test – Lowest Resolution preset