Hi steelpenguin,
you are my hero !
I have had that boring issue with my HD4000 and an ASUS VK266H Monitor as well.
On my 2 other machines with Windows 8 Pro x64 and Ubuntu x64 and different GPUs also attached to the KVM switch I did not have such problems.
Thank you very much for your posting, your solution is working for me - you made my day :-)
Best wishes
Sigi