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

iPhone 17 Pro 3 4ths Perspective Aluminum Camera Module 1

New iPhone 17 Pro Details: Brighter Display, Best Battery Life, and More

Wednesday September 3, 2025 5:33 am PDT by
Apple's iPhone 17 Pro and iPhone 17 Pro Max models will feature a number of significant display, thermal, and battery improvements, according to new late-stage rumors. According to the Weibo leaker known as "Instant Digital," the iPhone 17 Pro models will feature displays with higher brightness, making it more suitable for use in direct sunlight for prolonged periods. The iPhone 16 Pro and...
iPhone 17 Pro Iridescent Feature 2

iPhone 17 Pro Clear Case Leak Reveals Three Key Changes

Sunday August 31, 2025 1:26 pm PDT by
Apple is expected to unveil the iPhone 17 series on Tuesday, September 9, and last-minute rumors about the devices continue to surface. The latest info comes from a leaker known as Majin Bu, who has shared alleged images of Apple's Clear Case for the iPhone 17 Pro and Pro Max, or at least replicas. Image Credit: @MajinBuOfficial The images show three alleged changes compared to Apple's iP...
iPhone 17 Pro Iridescent Feature 2

iPhone 17 and iPhone 17 Pro Prices Estimated Ahead of Apple Event Next Week

Tuesday September 2, 2025 1:50 pm PDT by
Just one week before Apple is expected to unveil the iPhone 17 series, an analyst has shared new price estimates for the devices. Here are J.P. Morgan analyst Samik Chatterjee's price estimates for the iPhone 17 series in the United States, according to 9to5Mac: Model Starting Price Model Starting Price Change iPhone 16 $799 iPhone 17 ...
iphone 16 pro ghost hand

iPhone 17 Pro: 5 Reasons Not to Upgrade This Year

Monday September 1, 2025 4:35 am PDT by
Apple will launch its new iPhone 17 series this month, and the iPhone 17 Pro models are expected to get a new design for the rear casing and the camera area. But more significant changes to the lineup are not expected until next year, when the iPhone 18 models arrive. If you're thinking of trading in your iPhone for this year's latest, consider the following features rumored to be coming to...
iPhone 17 Pro Dark Blue and Orange

iPhone 17 Release Date, Pre-Orders, and What to Expect

Thursday August 28, 2025 4:08 am PDT by
An iPhone 17 announcement is a dead cert for September 2025 – Apple has already sent out invites for an "Awe dropping" event on Tuesday, September 9 at the Apple Park campus in Cupertino, California. The timing follows Apple's trend of introducing new iPhone models annually in the fall. At the event, Apple is expected to unveil its new-generation iPhone 17, an all-new ultra-thin iPhone 17...
Apple Watch Ultra 2 Complications

Apple Watch Ultra 3 Coming Next Week: Eight Reasons to Upgrade

Thursday September 4, 2025 7:38 am PDT by
We're only days away from Apple's "Awe dropping" fall event scheduled to take place on Tuesday, 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...

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)