UR44 and Cubase

Well, I have this annoying problem, no matter the size of a cubase project, after a while theres heavily drop-outs. Doesnt help to increase buffer size. Ironical it helps to switch Multi Processing in the Device meny OFF. But then I assume I only got one core to do the work?
This also affect MIDI. Midi in signals gets huge delays. What is this, crappy drivers??

Z87 MB with Intel 4770K

What operating system are you on? What version and build of Cubase is it (Help, About)?

In Devices, Device Setup, VST Audio System, what is your ASIO driver set to? What is your Input Latency?