Hello Dr.Romca,
I first want to thank you for your patience on this.
We have received feedback from other customers reporting that the issue has been fixed by installing the latest BIOS for the DZ87KLT-75K, DH87RL and DQ87PG along with the latest graphics driver. In your case, You need to access downloadcenter.Intel.com and get the latest updates for this unit.
I would like you to check for these drivers and BIOS updates and install them on your computers and provide feedback.
We also have released a BETA graphics driver that we would like you to test and provide feedback about it. Here is the download link:
https://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=23858
You can provide feedback for this BETA driver at this post:
https://communities.intel.com/thread/51391
For those who want to provide more feedback related to the Driver version 3496, please post here: