I don't care what anyone says. I've tried SO MANY ultrabooks with HDMI to work with my 2560x1600 desktop monitor, a 2013 model U3014. It also doesn't work with various 1440p monitors that I've used - including the Samsung S27B970, S27A850, and the Dell u2713. HDMI DOES NOT PROVIDE HIGHER THAN 1080P.
1440p and 1600 DO NOT WORK VIA HDMI. NO MATTER WHAT ANY SPECIFICATION SAYS, IT WILL NOT WORK. 99.9% of HDMI implementations are 1080p only, and that includes EVERY ultrabook. Furthermore, you can try using a desktop GPU with HDMI on a 1600p or 1440p monitor. You will be stuck at 1080p - this is true of the GTX 680, GTX 780, and 7970. HDMI limits the output to 1080p, because 99.9% of HDMI implementations are either old are don't fully implement the specification - therefore limiting it to 1080p.
This is garbage. This is why I won't buy such an ultrabook, period. Sure, you can say that it doesn't matter to some users. It matters to me. It matters to those folks who use non garbage portable computers from Apple. Apple doesn't saddle their macbooks with HDMI, do they? And what sells more? Macbooks or ultrabooks? I'll let you all ponder that. I don't give a flying eff about some guy with a HDTV whining about how the least common denominator doesn't matter to them. Mini DP works with everything, you can find adapters to make it work via HDMI, VGA, and all of that nonsense - but you cannot make HDMI display higher than 1080p. It will not work with anything BUT 1080p.
Until ultrabooks use mini displayport, they will not be getting my money. This is actually why i've bought nothing but macbooks as of late. Using 1080p on my 1600p monitor is NOT ACCEPTABLE. Obviously this has been a source of frustration to me. I cannot use my desktop 30" at 1080p. Screw that.
I'm sorry for the tone but this a MAJOR source of frustration for anyone using a greater than 1080p monitor. Don't give me the nonsense "only a few people own such monitors". This is why Apple wins all of those sales, and ultrabooks don't. Apple doesn't sell lowest common denominator garbage, which is what HDMI currently is - as mentioned it just does not work higher than 1080p. Period. Until HDMI 2.0 is released I don't expect that to change. The other point being, is mDP can work with VGA, DVI, and all of that jazz but you can't make HDMI work with 1440 or 1600p. That's the problem.
So as I said. Until this is fixed. Money is going to Apple , since they're one of the few manufactures who don't release lowest common denominator nonsense.