Thanks for the idea. I was reading this thread, but didn't expect that the result from the monitor being connected to 1 of the GPUs will be so significant. I was rather thinking that it will up to few MH/s.
Now that I have connected the monitor to the iGPU via DVI-D <-> HDMI it works OK. Thanks!
You read it carefully? After your answer i don´t think so.
Your 4GB cards can´t mine eth in a few weeks, because the DAG becomes to big (current it is 3,8gb). If you connect a monitor to the first gpu, it will reserve some vmem and so the first gpu has not enough vmem.