That's normal with segmented tasks per page. It will be dynamic. whereas Firefox is aggregated. This makes the main Process more stable in case one page hangs due to kiddy scripts.
It's not bad, just a different philosophy with shared resources but separate cached memory per page on DLL's. It is support to make CHrome faster and more robust at the expense of RAM I have 5 tabd open in firefox for example using 0.5GB of Private Bytes and 0.6GB of Working Set. but a peak working set of 1GB for Firefox.
THe browser is design to use as much free Memory and leave sufficient for other processes by dynamically changing the working set request and OS allows what is available,
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Since RAM is cheap, you ought to have at least 4GB or more with x64, otherwise you need to choose leaner apps overall.