Latest WebKit Builds Address Browser Scrolling Performance on Retina MacBook Pro Models

Soon after the launch of the 15-inch Retina MacBook Pro in June, we pointed to an analysis by AnandTech showing how the need to drive a massive number of pixels taxed the graphics capabilities of the machine to the point where it struggled to hit 20 frames per second while scrolling on resource-intensive web pages such as Facebook news feeds.

AnandTech now follows up with a new report based on a thread in our forums showing that the latest builds of WebKit, the open source browser engine upon which Safari is based, demonstrate dramatically improved frame rates during scrolling.

I grabbed a build (r135516 - it's no longer the latest build but I assume the later builds also contain the fix) and tried it out on the 13-inch rMBP. Scrolling down my Facebook news feed ended up being one of the best showcases for poor scrolling performance on the rMBPs, so that's obviously the first test I ran. As always I used Quartz Debug to measure UI frame rate.

The results show frame rates of around 20 frames per second (fps) under the standard Safari 6.0.2, but jump to nearly 50 fps when using nightly build r135516 of WebKit.

webkit retina frame rate
Frame rates approaching 50 fps when scrolling in WebKit nightly build r135515

AnandTech hasn't been able to determine exactly what code changes were made to enable the significant boost to scrolling performance on Retina MacBook Pro models, and it is unclear exactly when those changes will be incorporated into Safari itself, but it certainly seems that a solution is on its way.

Related Roundup: MacBook Pro

Popular Stories

WWDC25 Live Coverage Feature 1

WWDC 2025 Apple Event Live Keynote Coverage: iOS 26, macOS Tahoe, and More

Monday June 9, 2025 9:00 am PDT by
Apple's Worldwide Developers Conference (WWDC) starts today with the traditional keynote kicking things off at 10:00 a.m. Pacific Time. MacRumors is on hand for the event and we'll be sharing details and our thoughts throughout the day. We're expecting to see a number of software-related announcements led by a design revamp across Apple's platforms that will also see the numbering of all of...
maxresdefault

Everything Apple Announced at WWDC 2025 in 9 Minutes

Monday June 9, 2025 5:21 pm PDT by
At today's WWDC 2025 keynote event, Apple unveiled a new design that will inform the next decade of iOS, iPadOS, and macOS development, so needless to say, it was a busy day. Apple also unveiled a ton of new features for the iPhone, an overhauled Spotlight interface for the Mac, and a ton of updates that make the iPad more like a Mac than ever before. Subscribe to the MacRumors YouTube channel ...
liquid glass

Apple Announces All-New 'Liquid Glass' Software Redesign Across iOS 26 and More

Monday June 9, 2025 10:13 am PDT by
Apple today announced a complete redesign of all of its major software platforms called "Liquid Glass." Announced simultaneously for iOS, iPadOS, macOS, watchOS, tvOS, visionOS, and CarPlay, Liquid Glass forms a new universal design language for the first time. At its WWDC 2025 keynote address, Apple's software chief Craig Federighi said "Apple Silicon has become dramatically more powerful...
iPadOS 26 Apple Newsroom

Apple Says iPadOS 26 is Compatible With These iPad Models

Monday June 9, 2025 11:22 am PDT by
Apple today announced that iPadOS 26 will be compatible with the iPad models listed below. iPadOS 26 features a new Liquid Glass design, a menu bar, improved app windowing, and more. iPadOS 26 supports the following iPad models:iPad Pro (M4) iPad Pro 12.9-inch (3rd generation and later) iPad Pro 11-inch (1st generation and later) iPad Air (M2 and later) iPad Air (3rd generation and...
iPhone Car Key WWDC 2025

Apple Says These 13 Vehicle Brands Will Soon Offer iPhone Car Keys

Monday June 9, 2025 2:38 pm PDT by
In 2020, Apple added a digital car key feature to its Wallet app, allowing users to lock, unlock, and start a compatible vehicle with an iPhone or Apple Watch. The feature is currently offered by select automakers, including Audi, BMW, Hyundai, Kia, Genesis, Mercedes-Benz, Volvo, and a handful of others, and it is set to expand further. During its WWDC 2025 keynote today, Apple said that 13...
Apple WWDC25 iOS 26 hero 250609

Apple Announces iOS 26 With 'Liquid Glass' Design, Live Translation, Overhauled Phone App, and More

Monday June 9, 2025 11:00 am PDT by
Apple at WWDC announced iOS 26, introducing a comprehensive visual redesign built around its new "Liquid Glass" concept, alongside expanded Apple Intelligence capabilities, updates to core communication apps, and more. Liquid Glass is a translucent material that reflects and refracts surroundings to create dynamic, responsive interface elements, according to Apple. The new design language...

Top Rated Comments

Justin941 Avatar
163 months ago
Blur out the names or someone's getting pizzas sent to thier house
Score: 9 Votes (Like | Disagree)
nuckinfutz Avatar
163 months ago
So why did Apple release a product that clearly wasn't ready yet?
When is anything every ready in this industry?

Everything is in constant motion.
Score: 7 Votes (Like | Disagree)
nuckinfutz Avatar
163 months ago
Apple didn't do anything, webkit did which is mostly people from KHTML which is what webkit was forked from.

That was ages ago. Today's webkit is a much larger beast than that old KHTML. Go ask Dave Hyatt how much work he's put into Webkit as an Apple employee.

To say Apple hasn't make a significant investment in Webkit is to be either ignorant or foolish or both.
Score: 4 Votes (Like | Disagree)
CausticPuppy Avatar
163 months ago
Sweet.

It's a shame so many "trusted" review sites (including The Verge) dinged the rMBP and blamed the hardware.... for what is clearly a software problem.
Score: 4 Votes (Like | Disagree)
ironsienna Avatar
163 months ago
Great, that was the major concern I had that was holding me from purchase a new macbook pro: Poor web browsing performance. Kudos to Apple, for working on optimising the code rather than trying to sell another model with faster processor in just a few months. I am so glad they managed to address this as it was rather irritating...
Score: 4 Votes (Like | Disagree)
KnightWRX Avatar
163 months ago
That's incorrect and has been pointed out a gazilionth times here. It has everything to do with pixel pushing power, the ACD might have the same resolution with the 13" mbp, in the later the resolution is doubled and then halved (or adjusted to some %) to fit the screen. Thus it's the overhead to run 4 ACDs (no of pixel quadrupled) not one, plus the processing cost of then adjusting it to the actual screen size. When the no of pixels you render are QUADRUPLED you bet it has everything to do with pixel pushing power.
You're saying the same thing I am except making a few wrong assumptions. The resolution isn't doubled then halved at all in HiDPI mode, it's only downscaled after upscaling if you use the scaled modes (1680x1050 or 1920x1200). Running at 1440x900 (2880x1800) only upscales non-Retina graphics to 2880x1800 and leaves it at that. Running 1920x1200 (which I run permenantly) runs a 3840x2400 framebuffer which it then downscales to 2880x1800 for displaying on the display.

And what I've been saying all along is quite correct, the problem is not the pixel pushing ability of the GPU. Pixel fill rates, look them up. Again, if you can't understand that a 4 year old GPU, the 9400m, could power a 30" ACD and that we're now in 2012, 4 years later, with GPUs 3 generations newer, I don't know how to explain it to you.

The 9400m could push 2.32 GP/s. Again, 4 years ago. 2880x1800 at 60 fps is roughly 311 MP/s. Are you getting this ? Even if what you say is true and HiDPI was so horridly optimized as you claim (which it isn't), that's still only half of the pixel fill rate of a now 4 year old Integrated GPU.

Anyway, I own a rMBP 15" and I've hardly met any "lag" whatsoever. I guess some people are just too sensitive. Thank god Apple knows it's a software issue and is fixing it for those people.

----------

It's not a bs argument, it's not powerful enough indeed. The ui still lags and stutters. The current hardware is just not capable enough. It's an air cpu circa rev. 1. Apple have hacked their way to resolution independence with rendering twice the resolution canvas so as to avoid what win 8 did and go into detail about interface elements. They thus offloaded all the complexity on the hardware, and the hardware isn't there yet. Simple as that. Rev. 1 retina macbook pros are a major compromise. I am still planning to go ahead and buy one, fyi, but If I do I ll be do it in fully aware that I am buying a problematic rev. 1 product, not only for the image retention issue with the lg screen, but also for the gfx barely making it there.

The hardware is capable. You just don't understand GPU hardware or HiDPI to make such claims. Anand has always been full of it.
Score: 3 Votes (Like | Disagree)