gmod crashing

Having gotten a bit further on my garrysmod with constantly crashing I’m experiencing a new issue.

Everytime I open garry’s mod I have to change all my settings to “low”. Which looks awfull. I am then ableto join custom maps, however I still crash now and then attempting to a join the server.
Even with my settings on low if a new entity or effect spawns such as “snow” on RP my game would crash (hl2.exe has stopped responding).

I have the ATI Radeon HD 5670 graphics card I don’t think I should be experiencing any problems with it.

ERROR LOG: http://dumps.garrysmod.com/?view=1821927058&refresh=28

I’ve re-installed the game twice, deleted cache and verified.