Tab hoarders rejoice: Firefox is about to get ridiculously good at handling large number of tabs.

Firefox 55, due for release at the start of August, will feature a series of improvements to the browser’s responsiveness when multiple tabs are open.

This work is part of something called Quantum Flow, a Mozilla engineering project to fine-tune and tweak the browser’s overall performance.

Opening 1691 tabs in Firefox 55

Mozilla’s Dietrich Ayala decided to test how well various versions of Firefox copes with 1691 open tabs. He launched the same custom profile in multiple versions versions of Firefox, including Firefox 55 and 56, on his MacBook and measured the time the browser took to open:

As you can see: Firefox 55 with the quantum flow changes, takes just 15 seconds to open (but not load) 1691 tabs. By contrast, Firefox 51 takes almost 8 minutes to do the same thing.

Ayala’s tests, while extreme, do show how inefficient Firefox had become, but is now improving from. He adds “more effort is being put into making Firefox fast than I’ve seen since… well, since I’ve been working on Firefox. And I’ve been at Mozilla for more than a decade.”

The gains don’t end at faster opening times, either. Memory usage is also massively reduced:

firefox 55 memory usage

Again, this is without all 1691 tabs being loaded. The tabs are simply open with the network off.

Will these gains be less appreciable in real-world usage? Perhaps. Firefox doesn’t take that long to open with a couple of tabs on my Ubuntu install.

But when combined with other recent initiatives and technologies, like multi-process mode and the Photon UI improvements, they point to a far faster Firefox in the offing.

Thanks Lutz

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