I only use about hundred tabs (not hundreds) but I find Opera best in this regard - mostly because memory usage, stability (as opposed to chrome) and capability of the UI to handle that many tabs while being usable. The thing is, I don't turn the browser off. Maybe once a month to install Windows updates.
There's an ugly workaround though - start Opera without internet connection and then reload tabs as needed.
FF has lazy loading. Options->General->Don't load tabs until selected.