Performance has always been one of the core pillars of Chrome and it’s something we’ve never stopped investing in. Publicly available and open benchmarks, which we create in open collaboration with other browsers, are useful tools for tracking our overall progress, understanding new areas of improvement, and validating potential optimizations. In today’s The Fast and the Curious post, we’d like to go through Chrome’s recent work that enabled it to achieve the highest score ever on the Speedometer benchmark.
For Speedometer, these optimizations have resulted in a 10% improvement since August 2024. That 10% improvement leads to better browser experiences, higher conversions for businesses, and deeper enjoyment of what the web has to offer. If each Chrome user used Chrome for just 10 minutes a day, these improvements collectively save 58 million hours or roughly 83 lifetimes worth of waiting around for websites to load and do things.
Speedometer 3 score measured on Apple Macbook Pro M4 with MacOS 15
Speedometer is a benchmark created in open collaboration with other browsers and measures web application responsiveness through workloads that cover a large variety of different areas of the Blink rendering engine used in Chrome:
In essence, Speedometer tests critical components of the entire rendering pipeline. For a deeper dive into these individual parts, we recommend the presentation Life of a Script at Chrome University.
Achieving exceptional web performance requires a multifaceted approach, and optimizing for Speedometer is a testament to overall product excellence. Over the past year, our team has focused on refining fundamental rendering paths across the entire stack. Here are some notable optimization examples.
The team heavily optimized memory layouts of many internal data structures across DOM, CSS, layout, and painting components. Blink now avoids a lot of useless churn on system memory by keeping state where it belongs with respect to access patterns, maximizing utilization of CPU caches. Where internal memory was already relying on garbage collection in Oilpan, e.g. DOM, the usage was expanded by converting types from using malloc to Oilpan. This generally speeds up the affected areas as it packs memory nicely in Oilpan’s backend.
Strings in the renderer improved quite a bit over the last year by avoiding costly representations where possible and switching hashing to rapidhash. More generally, lots of data structures were equipped with better hashes, filters, and probing algorithms.
Where rendering becomes inherently expensive, e.g., for computing CSS styles across various elements, caches are now used much more effectively with better hit rates. At the same time we cache fewer things that are not relevant. Another area where rendering becomes expensive is font shaping; the team significantly improved Apple Advanced Typography font shaping performance which is relevant everywhere text is rendered.
Posted by Thomas Nattestad
Notifications in Chrome are a useful feature to keep up with updates from your favorite sites. However, we know that some notifications may be spammy or even deceptive. We’ve received reports of notifications diverting you to download suspicious software, tricking you into sharing personal information or asking you to make purchases on potentially fraudulent online store fronts.
To defend against these threats, Chrome is launching warnings of unwanted notifications on Android. This new feature uses on-device machine learning to detect and warn you about potentially deceptive or spammy notifications, giving you an extra level of control over the information displayed on your device.
When a notification is flagged by Chrome, you’ll see the name of the site sending the notification, a message warning that the contents of the notification are potentially deceptive or spammy, and the option to either unsubscribe from the site or see the flagged content.
An example of a notification flagged as possibly spam.
If you choose to see the notification you will still see the option to unsubscribe or you can choose to always allow notifications from that site and not see warnings in the future.
What you see when viewing a flagged notification.
How It Works
Chrome uses a local, on-device machine learning model to analyze notification content. This model identifies notifications that are likely to be unwanted. The model is trained on the textual contents of the notification, like the title, body, and action button texts.
Notifications are end to end encrypted. The analysis of each message is done on-device and notification contents are not sent to Google, to protect user privacy. Due to the sensitive nature of notifications content, the model was trained using synthetic data generated by the Gemini large language model (LLM). The training data was evaluated against real notifications Chrome security team collected by subscribing to a variety of websites that were then classified by human experts. To start, this feature is only available on Android as the majority of notifications are sent to mobile devices, however we will evaluate expanding to other platforms in the future.
This feature is just one of many ways Chrome works to reduce the number of potentially harmful notifications you receive. Other ways Chrome protects against potentially harmful notifications include:
In Safety Check you can review any notification permission revocations
Notification warnings are an important step in Chrome's ongoing commitment to user safety. The Chrome Security team in partnership with Google Safe Browsing continually monitors threats to our users in order to evolve our defenses against abusive activity across the web. Keep an eye on our blog for updates on how we are helping you stay one step ahead of online threats.
Since Google announced the Chromium project in 2008, we have been excited to build on the great foundations of open-source web browsers and contribute to the continued development of a rich web platform. Today, Chromium is used by hundreds of different projects globally, including big browsers like Chrome, home electronics from LG, application frameworks like Electron and even custom applications like Bloomberg terminals and SpaceX capsule control software.
In 2024, Google made over 100,000 commits to Chromium, accounting for ~94 percent of contributions. While we have no intention of reducing this investment, we continue to welcome others stepping up to invest more.
Google also continues to invest heavily in the shared infrastructure of the Open Source project to "keep the lights on", including having thousands of servers endlessly running millions of tests, responding to hundreds of incoming bugs per day, ensuring the important ones get fixed, and constantly investing in code health to keep the whole project maintainable. This work represents hundreds of millions of US dollars in annual investment just for maintenance costs before any new feature, innovation or other business priorities can be addressed.
Sustainable funding of critical open source infrastructure remains a hot industry-wide topic of discussion and over the years we’ve heard from many companies and developers about how critical the Chromium project is to their work. They’ve also shared how they would like to support the continued health of the project, beyond direct engineering support.
Today Google is pleased to announce our partnership with The Linux Foundation and the launch of the Supporters of Chromium-based Browsers. The goal of this initiative is to foster a sustainable environment of open-source contributions towards the health of the Chromium ecosystem and financially support a community of developers who want to contribute to the project, encouraging widespread support and continued technological progress for Chromium embedders.
The Supporters of Chromium-based Browsers fund will be managed by the Linux Foundation, following their long established practices for open governance, prioritizing transparency, inclusivity, and community-driven development. We’re thrilled to have Meta, Microsoft, and Opera on-board as the initial members to pledge their support.
We welcome this additional investment into Chromium’s commons and we’re looking forward to working with the other members of the Supporters of Chromium-based Browsers to ensure that it meets the needs of the wider Chromium community. At the same time, we remain committed to being the responsible steward of the Chromium project and to the massive investment necessary to keep Chromium working well for the entire web industry.
