I'm running HL2 Ep2 through Crossover Games 7 on a Macbook Pro 2.6 Penryn, 4GB, GeForce 8600M GT 512MB VRAM, and OS X 10.5.2. I'm also using -dxlevel 80.
I've found that I can run the game for maybe 10 minutes max at a time, before I get a freeze with looping audio.
I usually load the game, load a level, and then set the resolution to 1440x900 (or 1440x867 if using a virtual desktop; No noticeable change in stability between the two) and texture detail to high. The performance with these settings is fine (until it crashes, that is). I found that doing this before loading a level could sometimes cause a crash during loading.
Has anyone else had gameplay stability problems even after setting -dxlevel 80? HL2 and Ep1 ran just fine, Portal could be a bit crash prone at times.
I'm wondering if changing the resolution or texture detail in-game could be contributing to my problems. Is there a way to set them in the game's launch properties? And could that help?