Am I the only one here who thinks you'll have no problem at all running it?
The Source engine is AMAZINGLY scalable, and if I could play HL2 on an old FX5200 with a 1.8ghz celeron on highest possible settings in DX8 mode, I know you can get away with it absolutely fine. Alot of people forget the difference that simply switching to DX8 mode can make, and while you do lose some DX9 flair, it's the performance that should matter more to you.
Try out the HL2 demo anyway, if that runs well, I guarantee for the most part all of Orange Box will run just as well.








