On what machine? As I mentioned up thread, if a machine with similar specs can't handle that many tabs, something is misconfigured. Eg maybe memory timings are way too conservative or the wrong power profile is in use.

If you open Resource Monitor before the freeze, you can usually see what happened on the graphs. If you're fast enough, you can also click "analyze wait chain" to see something that looks like a stack trace. The graphs and trace should make it pretty obvious why an app is frozen. Eg maybe it's trying to save the history sqlite database and your SSD ran out of SLC cache.