As a non-technical person it just smells like Safari is out there nearly constantly writing your frequently visited websites in the background to gain this speed advantage.
In my situation on my M1 Macbook Pro, this is exactly what it was doing. And I observed this all the way back in December after noticing the unusually high SSD writes in Activity Monitor.
I tested Chrome, Edge, Safari, and Safari Technology Preview, with specific browsing use cases to make my comparisons as fair as possible. The memory usage from lowest to highest was clear: Edge, followed by Chrome, followed by both Safaris.
This was observed using Activity Monitor over atleast a couple of days for each because I figured if I was going to switch browser, it would be to the ‘correct’ one so I wouldn’t have to be concerned with it later on.
Safari is simply
too greedy with the way it writes parts of any and every website after closure into its ‘Safari Web Content (Cached)’, which was truly causing my M1 to swap like crazy, and SSD writes were up to even 1TB+ after just two days. Yes, the way it caches so aggressively does mean that on slower connections it will appear faster because of said caching, but this seems to be done at the expense of all this caching and consequently SSD lifespan.
Not only this, but ofcourse neither Safari has any ‘Sleeping Tabs’ or tab suspender feature, and there is only one tab suspender on Safari available which in my experience did not improve my SSD writes as the excessive caching was still occurring.
Edge/Chrome on the other hand, both have built in ‘Sleeping Tabs‘ which can be set to save resources after a tab is unused for an x period of time. Effectively it’s like sleeping a background application that is idle - tabs with text input or with media playback are ignored. Additionally, they have much wider selections of extensions available and countless tab suspension extensions. In my case I decided to go with The Great Tab Suspender 7.1.6, and I turned on all the memory saving features in there, and I went 11 hours yesterday with 40 tabs ‘open’ by the end of the day, with only 700MB of swap and 45GB of SSD writes. Additionally I’ve done the Time Machine tweak mentioned here, and I went into spotlight settings and limited indexing of file types I never search for (I only use it as an app launcher), as well as various system folders that I would never need to search anyway.
In my personal situation, it seems my excessive SSD writes are resolved. I’ve gotten to love Edge after switching to LastPass and some other cool extensions like Dark Reader which has changed evening/night browsing for me forever, and the suspending of background tabs is awesome and barely noticeable really as websites load back fast anyway.
That being said I’d still love Apple to address this safari caching/kernel_task/swapping issue, which is likely plaguing countless M1/BigSur users without them even realising, which could lead to premature mac deaths down the line and ultimately loss of reputation (why did you have to solder the SSDs apple
).
