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

AirPods Pro 3 Heart Rate Tracking Feature

AirPods Pro 3 Expected to Launch This Year With Key New Feature

Sunday August 24, 2025 7:16 am PDT by
Bloomberg's Mark Gurman expects Apple to release new AirPods Pro this year, and he said the earbuds will have a key new feature: heart rate monitoring. From his Power On newsletter today, with emphasis added:As for Apple's other devices, there's a lot in the fall pipeline — though many of the new products are only incremental upgrades. There will be Apple Watch updates, faster Vision...
iPhone 17 Pro on Desk Centered 1

iPhone 17 Pro Coming Soon With These 12 New Features

Sunday August 24, 2025 6:00 am PDT by
Apple's iPhone 17 Pro and iPhone 17 Pro Max should be unveiled in a few more weeks, and there are plenty of rumors about the devices. In his Power On newsletter today, Bloomberg's Mark Gurman corroborated a rumor that iPhone 17 Pro models will be "available in an orange color." Below, we recap key changes rumored for the iPhone 17 Pro models: Aluminum frame: iPhone 17 Pro models are...
Alleged iPhone 17 Pro Antenna Design

Two All-New iPhone 17 Colors Seemingly Confirmed

Monday August 25, 2025 4:22 am PDT by
Apple will offer the upcoming iPhone 17 Pro and iPhone 17 Pro Max in a new orange color, according to Bloomberg's Mark Gurman. Gurman made the claim in the latest edition of his Power On newsletter, adding that the new iPhone 17 Air – replacing the iPhone 16 Plus – will come in a new light blue color. We've heard multiple rumors about a new iPhone 17 Pro color being a shade of orange. The ...
iPhone 17 Air Thumb 2 Blue Electric Boogaloo

Apple Has Reportedly Considered Releasing iPhone 17 Air Bumper Case

Sunday August 24, 2025 12:40 pm PDT by
Apple has "considered" releasing a bumper case for the upcoming iPhone 17 Air, according to Bloomberg's Mark Gurman. Similar to the bumper case that Apple introduced for the iPhone 4 in 2010, Gurman said the iPhone 17 Air version of the case would cover the edges of the device, but not the back of it. Those bumper cases were made of rubber. Given that the iPhone 17 Air is expected to have ...
awe dropping event

Apple Event Announced for September 9: 'Awe Dropping'

Tuesday August 26, 2025 9:01 am PDT by
Apple will hold its annual iPhone-centric event on Tuesday, September 9 at the Apple Park campus in Cupertino, California, according to an announcement that went out today. The event will start at 10:00 a.m., with select members of the media invited to attend. At the September 2025 iPhone event, Apple will unveil the iPhone 17 lineup, which includes an all-new ultra-thin iPhone 17 Air. It...
Awe Dropping Apple Event Feature

Five Things to Expect From Apple's 'Awe Dropping' September 9 Event

Tuesday August 26, 2025 4:17 pm PDT by
Apple today announced its "Awe Dropping" iPhone-centric event, which is set to take place on Tuesday, September 9 at 10:00 a.m. Pacific Time. There are a long list of products that are coming, but we thought we'd pull out five feature highlights to look forward to. That Super Thin iPhone - Apple's September 9 event will see the unveiling of the first redesigned iPhone we've had in years, ...
Apple Watch Ultra 2 Complications

Apple Watch Ultra 3 Just Weeks Away: Eight Reasons to Upgrade

Wednesday August 20, 2025 6:44 am PDT by
We're only weeks away from Apple's annual iPhone event – rumored to take place on September 9 – and along with the new iPhone 17 series, we're going to get a new version of the Apple Watch Ultra for the first time since 2023. By the time the Ultra 3 is unveiled, it will have been two years since the previous model arrived. The intervening period has left plenty of room for enhancements,...
airpods pro 2 gradient

AirPods Pro 3: Four Key Design Changes Anticipated

Tuesday August 26, 2025 4:05 am PDT by
Apple hasn't updated the AirPods Pro since 2022 other than a shift from Lightning to USB-C, and the earbuds are due for a refresh. According to Bloomberg's Mark Gurman, Apple will launch AirPods Pro 3 later this year, and apart from new features like heart rate monitoring, we're also expecting a few design changes. The fourth‑generation AirPods offer useful clues to Apple's design cues for ...

Top Rated Comments

Justin941 Avatar
166 months ago
Blur out the names or someone's getting pizzas sent to thier house
Score: 9 Votes (Like | Disagree)
nuckinfutz Avatar
166 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
166 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
166 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
166 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
166 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)