Use adblock, stop visiting nasty websites and open less tabs. Problem is easily solved.

That's strange. How many tabs are we talking? Are they running something intense or just ordinary webpages?

I usually end up with a couple of browser windows on each of the 4 virtual desktops, and each window will collect a lot of tabs

With that much RAM, you could fit multiple OSes entirely into memory. That is simply a lot.

Depending on which OS we're talking, this could fit thousands of OSes, this could fit 4000 DOS + windows 3.11 sessions :)