Saving Space: Firefox’s Content Process Limit

Mozilla has a knowledge base article for RAM or CPU starved Firefox users. The multiprocess Firefox explaination stood out to me:

Using multiple content processes can further increase performance and minimize the impact of content process crashes.


You can set between one and eight content processes. The default is eight. Having more content processes can improve performance when using multiple tabs but it will also use more memory. You can reduce the number of content processes if your computer is running out of memory.

In an attempt to reduce the memory pressure on my laptop, I changed my content process limit to 1. It seems to work, although a quick test with psrecord1 suggested it only reduced 13% of memory usage.

  1. psrecord $(pgrep firefox) --include-children --duration 120 --interval 1 --log "firefox$(date +%s).txt" with each setting (8 processes, 1 process) after opening a set of tabs: open "" && open "" && open "" && open "" && open "" && open "" && open "" && open "" && open "" && open "" ↩︎