I post this because a lot of users here are now using DP for the first time with 4K displays. I have recently bought two Benq BL2411PT, and I started looking for Displayport to Mini Displayport cables to connect them to a pair of Mac Minis (which have Thunderbolt ports that accept Mini Displayport). I went to Monoprice and noticed customer complaints about their Displayport cables being non-compliant. There are apparently a lot of Displayport cables that connect pin 20, which is not supposed to be done. Connecting pin 20 feeds 3.3v back into your video card, which causes issues, and may even damage the video card so that it may affect whatever else you plug into it later. Belkin and Startech cables are noted to be non-compliant, and in this thread Monoprice is also noted to be non-compliant. Here's VESA's official comments on the issue, and if you go to their certified product database, you can search for Cables and see their very short list of cables that are known to be compliant and not connect pin 20. The only DP to mini-DP cables listed as compliant are made by Accell. $12 for the 1 meter and $20 for the 2 meter, quite a bit more than Monoprice's $5 cables. I don't see any evidence that Monoprice has noticed its customers' complaints, which surprises me. Edit: In a post later in this thread, I describe how Monoprice got back to me and explained that this is not an issue on their Displayport cables: "In regards to pin 20, the short answer is that yes it is connected. The mini displayport side is a cable that connects to a PCB (printed circuit board) on the displayport side. The PCB is part of the connector on the displayport end, so technically none of the wires actually reach the displayport connector because they are wired directly into the PCB. In order for pin 20 to be active though, the device it is plugged into has to be designed to utilize the power from pin 20 and make that connection. If it is not designed for that, pin 20 would stay completely inert." I am now using a Monoprice Displayport cable between my Mac Mini and my Benq monitor without any problems.