Hey, I got Steam working on my Macbook with Crossover Games. I downloaded the Portal demo to see how it worked before I bought any Source games, but I'm disappointed with the performance. I've seen videos on YouTube of people playing Counter-Strike: Source, Team Fortress 2, Half-life 2, etc., on Macbooks with similar specs as mine with better frame rates. I've tried changing the graphics details, directx level and running the game in a window but none of these things has really worked. I'm wondering if anyone has any suggestions as to how to tweak the game settings to make it run better, or if buying more RAM would be worth it to help this problem. I have a white Macbook with a 2.16 GHz Intel Core 2 Duo, 1 GB 667 MHz DDR2 SDRAM, Intel GMA 950 with 64 MB shared VRAM. Thanks!