A browser per se shouldn't be doing that.
Thing is, it probably isn't the browser
per se (other than some really nasty JavaScript perhaps). It's probably some add-on or plug-in ... and it's likely related to some particular web site(s) or page(s).
If for example there are animations (using whatever technology) on a web page that are happy to soak up 100% CPU ... then a sane browser will run those bits of itself, or plugins or whatever, at reduced thread priority, so that even if you're using 100% CPU you don't get the "freezing" because anything else you want to do runs at a higher priority.
So, Saab Dastard is probably right that you'd get a different result with a different browser (Firefox, IE, who cares,
different is probably the point here).
You should also check for any malware that might be running in the browser context.
You should also consider whether these "freezing" events correlate with visiting particular web sites, and if so maybe avoid those sites.