I would recommend to install the latest version of the Graphics Driver from our site, please visit Downloads for Intel® HD Graphics 4600 for 4th Generation Intel® Core™ Processors and reinstall the driver since you already have it installed, I would also recommend performing a manual installation of the driver. Here are the instructions for the Manual Installation Desktop graphics drivers — How to Manually Install a Driver in Microsoft Windows 8* or Windows 8.1*
Here is a helpful link that might help you to fix this issue;
The content on the above site is not controlled by Intel. This information is offered for your convenience and should not be viewed as an endorsement by Intel for the merchants or services offered there.
For further information you can check the following link Graphics Drivers — Errors Reported By Microsoft*.
Now, with the Dedicated Video Memory in most cases, the computer manufacturer has already configured the system to use the maximum amount of graphics memory that is possible for your particular computer model. Sometimes you can change these values through BIOS level, if there are no options available in the BIOS then is not possible to change it.
Check with your computer manufacturer if there are tips on increasing the amount of graphics memory for your computer model.
If you are interested in additional information see graphics memory frequently asked questions:
have also set the Dedicated Video Memory to 512MB in BIOS but it shows only 128MB in OS:
What was name of BIOS option you modified?
It's Gigabyte H97-D3H UEFI AMI BIOS.
I get no TDR if I set the Video Memory to <256MB
You shouldnt change the Intel Processor Graphics Memory Allocation option from default value (64M), that memory is used at boot time and have no effect on application performance. Intel Windows driver will request memory from OS management depending on current needs.
But that's Intel driver's bug.