2015 MacBook Air, why u no have Ultra HD?

Discussion in 'MacBook Air' started by sum yung guy, Mar 9, 2015.

  1. sum yung guy macrumors newbie

    Mar 9, 2015
    Intel HD Graphics 6000, Thunderbolt 2 - why no support for 3840 x 2160?

    Your new little brother with the HD Graphics 5300 has it. Why not you?
  2. SmOgER macrumors 6502a

    Jun 2, 2014
    I guess that's either software limitation (which can be bypassed) or simply a typo.
    Technically HD6000 can support up to 3840 x 2160.
  3. sum yung guy, Mar 11, 2015
    Last edited: Mar 11, 2015

    sum yung guy thread starter macrumors newbie

    Mar 9, 2015
    Hard to believe Apple would be so careless as to make a typo in such a basic tech spec... but it looks like that might be the case. They've just updated the "Using 4K displays and Ultra HD TVs with Mac computers" document here:

    It now says "You can use 4K displays and Ultra HD TVs with [...] MacBook Air (Early 2015)" - though only at 30 Hz. Another typo? The "tech specs" page still says 2560 by 1600. Have to wait and see which one is right I guess.

    It doesn't mention the new Macbook, probably because it isn't released yet. But I guess it will be limited to 30 Hz? Maybe ok for movies, but not ok for a retina-style desktop display. The new MacBook Pro 13 inch is listed as the minimum for 4K / Ultra HD at 60 Hz, but according to Intel the Air's processor should be just as capable:

    Apple continues to list support of 60 Hz only through the "MST hack" on a very few models of Mac and monitor, and no support listed for excellent monitors like the Samsung U28D590D - although people on Apple discussion forums report it working fine with OS X 10.10, at least on a Mac Pro, and...

    What a mess.
  4. nagual macrumors member

    Apr 4, 2012
    a mess indeed ... cannot get a straight answer about 4k @ 60, one source claiming these:

    "Thunderbolt 2 doesn’t increase the total bandwidth of the interface—you still get a total of 20Gbps. However, Thunderbolt 2 allows file transfers in either direction to use the full 20Gbps of bandwidth, while the original was capped at 10Gbps read and 10Gbps write. More importantly, Thunderbolt 2 introduces DisplayPort 1.2 support to the Airs, which when combined with the new Haswell GPUs will enable 4K output at 60Hz."

    "The 2013 Retina MacBook Pros included Thunderbolt 2 and DisplayPort 1.2, but GPU limitations meant the 13-inch model could only drive a 4K panel at 30Hz. The new Broadwell GPUs support 4K output at 60Hz over DisplayPort."

    If I do believe what they are saying it means I still cannot get 60hz on my SONY xbr49x850a which I am using as external monitor just because I have only one option to connect my MacBook Air through mini DisplayPort to HDMI. We all know that it is 30hz over HDMI now. HDMI version 2 is not available yet
  5. sum yung guy, Mar 14, 2015
    Last edited: Mar 14, 2015

    sum yung guy thread starter macrumors newbie

    Mar 9, 2015
    That's a typo too. MacBook Air with Thunderbolt 2 (2015) has Broadwell, not Haswell. That aside, the claim that the new CPU/GPU will enable 4k output at 60 Hz seems to be supported by Intel info, but contradicted by Apple info.

    If you look at the Intel link above, under "Display and Audio Features Comparison", it says Haswell (4th generation) supports only 30 Hz, while Broadwell (5th generation) supports 60 Hz. But the Apple link says the Broadwell MacBook Air supports only 30 Hz - while the MacBook Pro Retina 13" supports 60 Hz, even though they both have Broadwell U-processors that should support it.

    The new MacBook's Core M processor on the other hand is listed by Intel as being 60 Hz "capable" but with "additional cooling required". So I would bet that Apple's fanless design is not going to support that. But why the new MacBook Air wouldn't support 60 Hz is a mystery to me.

    Some Sonys do support HDMI 2.0 already. To use an Ultra HD TV as a desktop computer monitor via HDMI, the TV needs to support HDMI 2.0 *and* full chroma sampling at 60 Hz:
    ...then you have to wait a few months from now to buy a DisplayPort 1.2 to HDMI 2.0 adapter:

    Unfortunately, I think your X850A doesn't support that - not sure.

    This is all in theory though - at the moment we don't know which Macs (if any) would support 60 Hz Ultra HD through such an adapter.
  6. sum yung guy thread starter macrumors newbie

    Mar 9, 2015
  7. sum yung guy thread starter macrumors newbie

    Mar 9, 2015
    Well, there you go. There actually was a typo on the spec page, which has now been corrected:
    Ars Technica went out and bought one, connected it to a Dell P2415Q 4k monitor, and... 60 hz success!

    It's not 100% perfect, but it does actually work as I thought it should.

    That Dell monitor uses single-stream transport, which new monitors will have. Older monitors that rely on multi-stream transport are still listed on Apple's support page as supported by MacBook Pro 13", but not by MacBook Air. Who knows whether that can be believed or not?

    So, mystery solved... mostly.

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