I've got 188.8.131.52 installed on an HD 4000 configuration right now, and I'm seeing both options for manual tuning, as well as specific tab for graphics overclocking.
Can you try downloading the latest from here; Download Center
Let me know if this works.
@waynebliss: Sorry for the delayed response. This is most likely a setting that your OEM has disabled, which is why you aren't provided the option with XTU.
@Son Nguyen Duc: Are you using the Intel® Extreme Tuning Utility™ and are also unable to see an option for overclocking the graphics core of your processor?
Hi Jake. First off, are you using the latest version of the Intel® Extreme Tuning Utility for Windows 8? (Here's the link; Download Center)
Also, are you running the display off of Intel® graphics, or a discrete graphics card in your system? If your OEM has disabled the use of overclocking, it may manifest itself differently than other blocked users due to it being from a different OEM.
There is an ( i ) button next to the enable/disable button, as well as an ( x ). Does the 'i' give any useful info?
You might also check your BIOS and see if you can toggle/change the max graphics frequency to something higher than 350 MHz.