Well, I recently installed the Orange Box onto my computer. I must say, it is flat out amazing. I have a Radeon X1600 series Graphics Card, 3GB of Ram, Intel Core 2 T7200 Processor @ 2.0 GHZ. I can run all games fine, High model detail, Full reflections, etc. Then, comes portal. I can run portal on max setting's, BUT I have this skipping problem. I will start up Portal, and it works fine. But when i turn around, it freezes, until I turn the other way, then it unfreezes. It does it randomly, and in quick succession, It is quite annoying. I have tried running portal on other settings as well, still no dice. Any suggestion's or fixes one might recommenced? And, this is after i re-installed twice. lol. Sorry, I coppied it from yahoo answers :b
Try Right clicking Portal and checking gamecache if not try. -dxlevel 80 ? If not Right click portal set game launch parameter (I'm doing this off of memory so sorry if i skip a step or something) type in -dxlevel 80 click ok an launch. *Note This will severely kill the graphics You can get your graphics back by removing -dxlevel 80 from launch parameter. You can also try -dxlevel 90. If this error still happens contact Steam If They cant solve this (with your permission) I could help you remotely Via teamviewer