One of the tips on the linked page is to instruct the browser to use /tmp as its cache, after putting /tmp into RAM.
That may be no longer necessary.
In Firefox go to about:cache
and see the current status.
If you see something like this:
Memory cache device
Number of entries: 339
Maximum storage size: 29696 KiB
Storage in use: 2571 KiB
Inactive storage: 2571 KiB
Then you do not need to do anything. If it is not like that then you can change the settings.
Go to about:config
browser.cache.disk.enable false (this may not be needed)
Restart Firefox to check status: