Hi guys. I have connected my base 2015 MBP 15" to my 28" Samsung 4k Monitor. The mouse is a MadCatz RAT 5. The drivers are installed. Currently, keyboard and mouse are sluggish. Is this because of the integrated GPU? It can't produce good performance on this resolution? I was under the impression hooking up to a monitor of this size would be fine. It's very frustrating. I have tried playing around with the settings but I cannot seem to get anything working flawlessly.