I use Seamonkey 2.33, by default, and it showed 105 MB, after starting, settling down to 74 MB, 92 MB with mail open, or three tabs. Firefox 6.02, a notorious memory hog 126 MB. Chrome display , at least, seven chrome.exe items, which added up to over 150 MB.iexplore.exe had two items, which added up to 129 MB. Firefox 3.6.22, my favorite Firefox uses 88 MB, with three tabs. Does plugin-container.exe matter? Whose is it? With only Seamonkey open, it draws only 2 MB, much more when Firefox is open.
I had noticed, long ago, that the more tabs the worst, so all browsers display only two tabs on startup, with a maximum of three. I, never, leave any window open.
I noticed that some tabs take up more memory than others. Since I have an old computer, with 512 MB RAM, memory usage matters.
UserAgent: Mozilla/5.0 (Windows NT 5.1; rv:6.0.2) Gecko/20110902 Firefox/6.0.2 SeaMonkey/2.3.3