Solution: 1080p on MBA (and other heavy tasks)

Discussion in 'MacBook Air' started by andrewp, Mar 23, 2009.

  1. andrewp macrumors member

    Oct 24, 2008
    Some of you may already know this so please don't tear me down.
    I'm posting this because I've had problems with my MBA's performance for the last 3 months. It could never playback 1080p, and I killed myself while watching the stuttering on my 3000$ machine.
    To make it short the MBA (1,86ghz) features a powerful Intel L9400 processor. This processor is found in the new HP EliteBook 2530p that shares the same price as the MBA though way uglier.

    The problem with the MBA is that Apple has included a silly undervolting technology that basically decreases performance in order to maintain temperatures. This explains why the video is stuttering, it is running on 768mhz instead of 1,86. Come on Apple you could have found a better way to fight heat.

    Anyway, we don't want our MBA to run at 50% most of the time. That's why I tried the ever so famous coolbook application, and it has completely solved my problem with stuttering. Now I can tell my MBA to use 1,86 ghz whenever I do powerful tasks and it finally listens and acts like the computer I wanted it to be. Last playback of a 13gb 1080p file showed 0 skipped frames
  2. Scottsdale macrumors 601


    Sep 19, 2008
    Perhaps should have titled this Cool Book to the rescue on a rev B MBA? Seriously though, I have a rev B MBA, and I have never had a problem. I have never even considered installing Cool Book.

    The MBA has a 1.86 GHz SL9400, has 6 MB L2 Cache, and is a 45 NM, SSF Penryn CPU running at 17W (a Low Voltage chip). It is quite the worthy chip. I didn't realize Apple was doing anything special with this chip, but if true, disappointing...
  3. the vj macrumors 6502a

    Nov 23, 2006
  4. bossxii macrumors 68000

    Nov 9, 2008
    Kansas City
    Good to know :) I swapped out my Rev B for a MBP as the UMB screen blows and I watch alot of video. The stuttering was driving me nuts so I took it back. I had read about coolbook on the Rev A but didn't investigate and after spending nearly 40 days I only had 5 left to return it without a hassle.

    I'll hang out for the Rev C, really would like to see a speed bump, 4 gigs and a few other enhancement. It keeps pulling at me as it was a fun computer to use, can't beat the weight and form factor. Thanks for the tip and enjoy :)
  5. wetrix macrumors 6502


    Dec 1, 2006
    Auckland, New Zealand
    Except the 2009 Mac Pro strapped to a 30" ACD and a UPS.
  6. Stetrain macrumors 68040

    Feb 6, 2009
    You were watching 1080p video on a screen with 800 vertical lines? Why not just stick with 720?
  7. Mactagonist macrumors 65816

    Feb 5, 2008
    NYC - Manhattan
    I bet a lot of things beat it when it comes to playing HD video on a g4. :)
  8. still in school macrumors 6502

    Feb 21, 2009
    exactly what i was thinking to myself..
  9. imax2k2 macrumors regular

    Feb 25, 2009
    I dont know, but I have had no problems playing blu-rays and 1080p videos on my RevB, with no coolbook installed.

    No one else has similar experience? I play the blurays on windows though.
  10. Scottsdale macrumors 601


    Sep 19, 2008
    No need or desire to put Cool Book on my baby either. Rev B, at least mine, doesn't need anything as it is already PERFECT!
  11. andrewp thread starter macrumors member

    Oct 24, 2008
    Cause I hook it up with my 50" plasma with 1080 lines ;)
    Anyway, for those having no problems "without coolbook". What player did you use? I use Plex with default settings and it skipped frames after 10 secs with .mkv compression.
  12. darrellishere macrumors 6502

    Jul 13, 2007
    Im not convinced about cool-book yet! As it only seems to come into play with video playback. Maybe apple needs to tweak their own drivers in order to achieve the same effect.

    The apple drivers currently drop the frequency down when the chip is idle, and not receiving any commands, but it flips between the higher frequency and lower, causing unnecessary video freezing during hi def. playback.

    Although I think its the fact that anything below 2ghz core2duo, will not play 1080p HD? So maybe revision C, will cope better.
  13. Sijmen macrumors 6502a

    Sep 7, 2005
  14. EnderTW macrumors 6502

    Jun 30, 2007
    Yep. For certain mkv's and ts's my revb 1.6ghz would skip. I tried Plex, it slows it down. I also tried mplayer for osx, with the ffmpeg multi thread option, that didn't work that well.

    However, I don't get it. When the 1080p movie is playing, isn't the processor going at full speed? Wouldn't it force the processor to be using the full 1.86 ghz proc rather than at 800mhz? What does coolbook accomplish here?
  15. darrellishere macrumors 6502

    Jul 13, 2007
    You would think so, but it seems jump between the two. 798mhz & 1596mhz.
    on my 1.6 HDD (revb) still can't play 1080 with coolbook.

    Can the 1.86 SSD play 1080p .mkv without dropping frames using coolbook?
  16. dudeitsjay macrumors regular

    Mar 26, 2009
    Well, since you'd be running your cpu up by playing back 1080p, the cpu would generate lots of heat. Apple's innate solution to that was to downclock your processor to say 800mhz, which outputs less heat. What coolbooks does is, instead of downclocking to a lower clock frequency to combat the heat, it downvolts your cpu at its current clock frequency (or however you set it in coolbooks to do). So effectively, you're running less electricity through the cpu with coolbooks (hence called downvolting), reducing the heat it generates. It doesn't reduce performance when you downvolt, but it could have an destabilizing effect. Each chip is special so you have to tinker around with it to find the sweet spot. Right now on my MBA-B 1.6/HDD, I've got 1.6 at .9250V as opposed to the factory 1.0V settings. It used to stutter for HD playback, since the CPU would reach 90C, but now it reaches ~60C load and idle 43C. It's also because I reapplied thermal paste.

    Rarely do I get a stutter, even though my temperatures are fine, which is leading me to look at the slow harddrive as an issue. I hope when the prices on SSD aren't ridiculous, I'll be able to swap =\.

    There has been also reports of the differing OSes that can mean the difference between stutter and no stutter. Apparently, Windows XP/Vista can sometimes run a video stutter-free while OSX stutters. I wouldn't know too much about that though. First concern for stuttering video is heat. Fix it with coolbook and reapplying thermal (and voiding your warranty :D).
  17. EnderTW macrumors 6502

    Jun 30, 2007
    ahh that makes sense.

    I just don't think 1.6 ghz is powerful enough to play 1080p, depending on the bitrates of course. Which is perfectly fine. 720p plays just fine. I am probably going to buy a 24 inch imac for my home needs.
  18. EnderTW macrumors 6502

    Jun 30, 2007
    did you try through plex or only vlc?
  19. hohohong macrumors 6502a

    Jun 1, 2007
    I tried playing a 4GB M2TS file using VLC. It played for a few sec and video pause, but sound still plays on.

    So Air can't handle Full HD movie?

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