Retina Display: Scrolling & UI Performance

With the first Retina MacBook Pro I noticed UI performance in certain applications degraded considerably compared to previous, non-Retina MBPs. Browsing my Facebook news feed in Safari and scrolling down as well as just scrolling through a long email thread in Mail both caused frame rates to drop below 30 fps. Performing the same tests on my 2011 15-inch MBP yielded UI frame rates closer to 60 fps.


13-inch rMBP (left) vs. 15-inch rMBP (right)

The move to Mountain Lion improved UI performance, but it's still an issue. Switching between Retina and non-Retina MacBook Pros results in a very noticeable difference in UI frame rates, especially in problematic applications.

Apple does a lot of CPU and GPU work to make OS X look like OS X. Scaling the workload up from 1.76 million pixels to 4 and 5 million pixels creates additional work for both the CPU and GPU that neither chip vendor had planned on. Apple had to replace some fixed function code with general purpose CPU and GPU code to achieve consistent image quality in enabling Retina, which obviously has performance implications.

Next-generation GPUs should do a better job of driving these ultra high resolution displays, but today it looks like our biggest bottlenecks are software and single threaded CPU performance. In every situation where UI frame rate drops significantly on the rMBP, the offending application usually ends up consuming 100% of a single CPU core. This is true in Safari, Mail and other applications where I notice drops in scrolling frame rate.


The worst case UI perf

The worst case performance I recorded on the 13-inch rMBP was 16 fps when scrolling in Safari with Facebook loaded at the 1440 x 900 scaled resolution setting. Minimum frame rate at the default best for Retina setting ended up being around 18 fps. It's distracting and a clear regression from other, non-Retina Macs. That's the lowest performance you see, but not everything falls into that range. Scrolling down the AnandTech front page for example happens at around 40 - 50 fps at the 1440 x 900 scaled resolution. Other animations will happen as high as 60 fps, although you typically notice when things are slow not when they're performing as expected.


The better case

The 13 I'm testing had demonstrably lower scrolling performance than my 15-inch rMBP, but I believe that has to do with the difference in CPU clocks more than anything else. My 13 uses a 2.5GHz Core i5 that can turbo up to 3.1GHz, while my 15 has a max single threaded turbo of 3.6GHz - an increase of 16%. There's also the fact that the 15-inch model features a quad-core CPU, leaving you with more idle cores in the event that you're actually doing more than just scrolling all day. I suspect the combination of these two things is why a lot of folks perceive the 15-inch rMBP to deliver faster UI performance.

The 15-inch model does have a discrete GPU, however I didn't notice a big performance difference in UI frame rates when I was on integrated vs. discrete graphics. I do believe that a lot of the present issues are related to Apple not GPU accelerating more of the drawing pipeline and as a result, single threaded CPU performance suffering under the load of 4 and 5MP displays. Intel (and AMD) design their CPUs for the types of workloads most of their customers will be running. The vast majority of the market isn't running OS X with 4MP+ panels. A lot of this is related to OS X itself, as you don't have the same scrolling issues under Windows. As we saw in our Surface review, simply making an application (or in this case, an OS) look a certain way can eat up a good amount of CPU time.

There's not much you can do here other than wait for faster hardware or buy the fastest CPU available on whatever system you're considering. Single threaded performance will scale linearly with CPU clock speed, so higher clocked CPUs should deliver smoother scrolling performance. Ultimately just scaling CPU clock is an inefficient way to solve the current UI frame rate issues. Future revisions of OS X will likely shift even more UI workload to the GPU, plus we'll see new microprocessor architectures that will perform better with these types of workloads as well. The only issue is I don't know when either of these things will happen. Haswell should bring a good increase in IPC and maybe even a slight increase in frequency, which will definitely help.

What we'll need however, without any significant changes to OS X is an outright doubling of single threaded CPU performance. In the worst case scenario that could mean that we won't see UI frame rate fixed for years. I doubt it'll be that long, if I had to guess I would say that Haswell will bring a good improvement and around the Broadwell (2014) timeframe is probably we'll see things really get better. I don't have intimate knowledge of Apple's OS X roadmap and I also don't know the instruction mix that's causing this behavior so I can't really say anything for certain, I'm just speculating.

The 13-inch Retina Display in Numbers USB 3.0 Performance
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  • MrCromulent - Tuesday, November 13, 2012 - link

    Thanks for the thorough review! I was really looking forward to the 13" version of the rMBP as a possible desktop replacement machine for development, but I guess I'm going to pass this year.

    Multi-monitor performance (internal display plus 2 external ones) would be excruciatingly bad, I presume? Or is it acceptable because most of the stuttering seems to be caused by CPU issues instead of a GPU bottleneck?
    Reply
  • Freakie - Tuesday, November 13, 2012 - link

    I would encourage you to pass. This 13" rMBP has COMPLETELY lost it's "Pro" name. Dual-core with no dedicated GPU, only 8GB of RAM, paltry amounts of storage, and a screen that's only good for resolution, not for quality, makes this a stupid choice for any art professional. The thing can't even run a Safari window with Facebook on it without dropping below 30fps! Add the $1,700 price tag to all of this and you have to be out of your mind to buy it. And trying to multi-monitor is going to drive you nuts performance wise.

    And now for a slight rant on the Review it's self:
    "You don't sacrifice display quality at all in the move to the smaller panel. Brightness, contrast and color reproduction are all great."

    This line particularly bugged me, which shows Anand's bias for Apple yet again. Brightness is good, not great, and color reproduction is horrendous. You DO sacrifice a lot in switching to these displays. Artwork on this display is color suicide. And I haven't seen a computer screen have after images like you described in well over 6 years. In my opinion quality has gone WAY down.

    So not only is your built-in display crappy for work, but if you plug another screen in then suddenly you've maxed out your CPU's performance, and that's before you've even started working.

    I'm sorry, Anand, but this entire review seems to dock points off again and again, and yet you still manage to say that it's nearly perfect in your conclusion. While I do appreciate that you've been more forward towards issues on the devices in your Apple reviews as of the last few that you've done, in the end it seems like you just conveniently forget about them and write apologetically about them where as Dustin would, and does, expose all of a laptop's flaws and strengths and does a good job of not sugar coating or glazing over problems. When Dustin sees a machine not living up to what it is supposed to be, he doesn't pull back any punches and calls it out. It seems obvious that this machine is not "Pro" in any way imaginable and I really feel that should have been pointed out.
    Reply
  • guidryp - Tuesday, November 13, 2012 - link

    Nice Rant. Too bad it is nonsense.

    Horrendous color reproduction?

    The screen has the best contrast of any tested and the second best color accuracy. Also this is an IPS screen with superior color stability vs angle of view. Much better than the TN screens that occupy the vast majority of laptops. It is a fantastic screen in terms of resolution, color accuracy, contrast and color stability.

    Image retention is the only real fault and if it was a significant issue, return it.

    As far as it losing "Pro" status for not having quad core/discrete GPU, that is no change, it was like that last year as well. If this is your definition of Pro, I am sure you can find a suitable cheap Dell that has quad core.

    Bottom line. I do think it is probably early to jump to this Retina Model because of potential performance hiccups, and you are better off waiting for a Haswell model. But there is no need to resort to nonsense ranting to state that.
    Reply
  • Freakie - Tuesday, November 13, 2012 - link

    IPS means next to nothing. It's just one small part of the entire range of components and technologies that go into making a good display. IPS is chosen for high resolution displays for different reasons other than color.

    And it's Delta E value gains nothing from being second best, as best is so far ahead of it it's ridiculous. Anandtech's method of obtaining Delta E is taking the best value after repeating the test multiple times, and with how close it is to so many other monitors, and how even a screen being on for 5 minutes versus 10 minutes can affect screen color tests small amounts, it actually isn't that hard to summarize the test results by saying that it essentially has the same color representation as the 5 notebooks behind it.

    And Color Space is VERY important for artwork. It's nice to have a good Delta E but without a wide color space, you're still shooting yourself in the foot and your results will be noticeably inconsistent and will require a lot more fiddling within your editing programs to get right.

    And my definition of Pro is what the MBP used to be, a powerful laptop that could reliably be used for professional work when you aren't at your desk and that sacrificed some weight and size in order to deliver the power that you need. This MBP does not live up to the MBP name and should just be a regular Macbook (but of course they got rid of those and just turned the MBP's into normal Macbooks).

    But no thank you on the Dell :) I wouldn't never own one of their consumer models and their professional models are rather pricey. I'd rather just Build-To-Order a nice ASUS and pay the extra $100 for the 95% NTSC Gamut Matte screen.
    Reply
  • guidryp - Tuesday, November 13, 2012 - link

    95% NTSC screens are just about useless for 99.99% of users.

    We live in an sRGB/Rec. 709 world, and that should be the goal for most screens, and the Retina MBP is very close to this much more important standard. Actually Anand should actually report the sRGB match in his reviews since it is so much more important for most users.

    Wider gamut than sRGB screens simply cause more problems than benefits, causing jarring color inaccuracy as you move back and forth between color managed and non color managed applications.

    It is a fallacy to simply think, a bigger number is always better when it comes to color gamut.
    Reply
  • Freakie - Thursday, November 15, 2012 - link

    It's not for 99.99% of users, MacBook Pro's were meant for professionals, but now because Apple wants more money, they got rid of the regular MacBooks and put crappier hardware in their Pro's. So for the people who buy the Pro's because they need a Pro machine, a 95% NTSC DOES matter.

    And even in the sRBG the Retina displays suck. 64% of AdobeRBG is still below 90% sRBG so it doesn't get any extra points even if you wanted to try to argue that for some reason sRBG is better. And I would disagree that wider than sRBG is problematic, especially when switching between color managed situations. Yes, switching from a non-calibrated screen from a calibrated one is weird if the non-calibrated one sucks, but who cares? The whole point of having the wide gamut, calibrated screen is so that your work comes out correct, not so that your browser window looks right -_-

    And it's not fallacy :P When you're working on something that you're going to print, or display through high resolution means like digital signage or movies on a projector... Those devices and mediums that your are going to be displaying it through will have wide gamuts. Obviously print has a wide gamut, and most digital signage uses the same 32"+ high resolution high gamut displays, and a professional movie projector for films will also have the same. So if you work on your project on an sRBG screen you will be sorry when you see it displayed/printed elsewhere.
    Reply
  • jmelgaard - Thursday, November 15, 2012 - link

    I Seem to be confused here... But you seem to imply that you only belong in the professional segment if you use your computer for graphical work?...

    Damn... And here I thought I used mine for Professional Application Development... BUMMER!... Ill better start looking for another job, one with Pictures and Colors and Gamuts and Colors and OMG my head hurts now...
    Reply
  • WebJester - Tuesday, March 26, 2013 - link

    I see you glossed over the comment about calibration. Reply
  • aguilpa1 - Tuesday, November 13, 2012 - link

    Color reproduction was only part of his reasons for noting that there should be a distinct difference between a Macbook and a MacbookPro. I have to agree with him. The Pro was for Professionals that did not mind the extra weight or size as long as they could get the options and upgrades they needed. The fact that you mention stupidly that maybe he should go get a Dell if he wants a 4 core CPU should slap you in the face as obvious that the MacbookPro is not a Pro if a cheaper model offers what it does not. Reply
  • TEAMSWITCHER - Tuesday, November 13, 2012 - link

    I have been waiting for this review, because I already upgraded from an older 15" dual-core MacBook Pro to this laptop. I did notice the minor "choppiness" when scrolling web pages, but it's not intolerable. I was expecting the HD4000 to be a total dog at 3D. To my surprise it wasn't all bad. To be honest though, I play mostly older games.

    The display is easily...hands down...no questions about it...the best I have ever used. Game over - thank you for playing. Now, when I look at non-retina displays, I immediately notice the difference - and I don't like what I see. I desperately want a 27" Retina Thunderbolt display. Maybe they can add discrete graphics to the display for the best of both worlds. Please Apple, make this happen.

    But where this laptop really shines is it's portability. Having used a 15" Pro laptop for the last eight years, the difference is striking. I was tempted by the 13" MacBook Air, but the grey bezel around the screen felt like a step back from the edge-to-edge glass that I have grown to love. This feels every bit like the Pro Machine I have been using for the last three years. I can't express how comforting it was to drop so much weight, yet retain the same great keyboard, trackpad, quality construction, and performance. Truly an amazing feat and why the "Pro" moniker is deserved.

    This isn't the laptop for everyone, but for me...web browsing, coding, and just always having a great computer at my finger tips...it's pretty close to perfect.
    Reply

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