There is also an unfair comparison made in the article.

> A quick PCMag test shows that 10 Chrome tabs on a Windows 11 PC with 32GB of RAM and 2TB of NVMe SSD storage take up over 2,000MB, or 12.5% of PC memory, so there's still room for improvement (Hazel's massive Firefox session file is just 70MB).

Taking up nearly 2GB of RAM for 10 tabs sucks, but they seem to be comparing the size of the session on disk to the resident size of the loaded browser in memory, of course the memory footprint is going to blow it away.

well i have 4600 tabs, 13 windows, 18 tab groups and 130 firefox processes. htop shows me that while each browser process has about 3GB of virtual memory, all of them barely register any real memory use. so as far as i can tell, tabs do not use any memory.

Close Firefox then restore your session. Until you switch to a tab, it stays unloaded and consumes nearly no resources. The tab does stay resident in memory until you restart again, or otherwise suspend it.