Is there a downside to using SwitchResX to enable a rMBP 13" to run a 4k monitor like the Dell P2415Q or P2715Q, other than it running at 50Hz instead of 60Hz? Something I might be missing here? Disclosure if you hadn't guessed: I am a novice at specs and such. I want the larger screen for use with writing code. I really like the idea of paying twice the amount of money to get a MBP 15" if this works well. I figure with the money I save buying the low end rMBP 13" now, I could wait a year and buy another low end rMBP 13" that runs 4k as well or better than todays 15". So it seems like quite a waste to buy the 15" right now if SwitchResX works, and I do need to buy the laptop now. I can't really wait. If it works I would buy low end rMBP 13" with 8GB memory and pair it with either of these 4k Dells. I could possible still go with the Dell U2415H that ra004e likes by comparison to the P2414Q, but I may go to 27".