The last few days, I've been struggling to get my laptop (ThinkPad T530 with Optimus) working with my new 4k monitor (ASUS PB287Q). This monitor need to be connected wither with HDMI or with DisplayPort. I know as a fact, the DisplayPort is not wired to the Intel video card. It's only connected to the Nvidia card. The following post also confirm this fact: Tri-head display on linux Thinkpad W520 (Graphics Adventures).
The whole idea was to disable Optimus in the BIOS and only use the Nvidia graphics card. Power consumption is not much of an issue. I'm also very afraid to use bumblebee. Usually, this should be simple as disabling Optimus in BIOS and selecting "Discrete Card" as the only graphics card available, but it's not. Linux lockup during the start-up sequence. I don't get a prompt and the system get unresponsive to any input.
After alot of debuging and serach, I figure out to use "noapic" as kernel parameter is fixing this issue. It's a working solution. I've also post a bug request: #757618.