Dunno if thatīs much help, but i had two instances where that happened
1. my ram had a false bios-configuration, was clocked too fast, which caused expensive apps to crash, fixed it, hammer ran stable
2. some minor background application, canīt remember what, somehow made hammer bug out and crash. had to do the timeintensive check by disabling all apps except windows-native and source+hammer. then, one by one, i started the apps that ran normally, until i found the bugger...
In the tools/options several things can help.
make your model render distance small, make your far clipping plane small, turn down details... Lots of options and I don't have Hammer open.
It can suck to try and view the entire scene like this, but it's managable.
I have a pretty decent comp, but once I get alot of stuff going I get weird graphic glitches and have to reboot if I have too much stuff showing.
I've never had Hammer crash my computer, but these glitches might as well because they last even after I shut Hammer down, but are gone after reboot.
You can also turn off models in 2d when not editing them specifically.
Also use the cordon tool so you are only looking at what you are working on.
If you aren't working on certian things like objects/placement you can turn off that vis group while you are working too.