let's test this. only one tab up viewing this page.
five minutes without script

five minutes with script

barely noticeable, the more tabs you have (depending what is on each, plus the longer you're on) seems to increase the memory regardless
note that Google Chrome uses one process per tab, not one process for the entire browser (520,688K was the memory usage for only that tab)
also, "five minutes" isn't a fair comparison
while using this script i also get noticeable overall browser slowdowns after a while