Check Bios settings and check your motherboards website.
Sometimes Ram cards can be Underclocked with default motherboard bios settings.
Example, i bought 1600hz DDr3 ram, and the default Bios was trying to run it at 1066hz, i thought i bought 1333hz, so thats what i changed it to, to find out 1 year later i had the 1600hz.
going from 1066hz ram to 1600hz is a pretty big difference lol... Thats why sometimes ram can build up.
The only reason google chrome would use more than 2.5 GB by itself, is if your on a dating website, or a porn website for webcams, JS.
had that problem a couple years ago.