http://www.gamersdepot.com/interviews/gabe/001.htm
GD: ATI has been blatantly obvious about its relationship with Valve. Can you tell us a bit about how that came to be? Gabe: We've had a lot of relationships over the years, with companies like Intel and AMD, with NVIDIA and ATI, and so on. What we look for are relationships that help us build better products or are in the best interests of our customers. Once we started to understand the performance of the various chipsets running DX9, it became pretty clear to us who we should work with to deliver the best hardware/software combination to our customers.GD: What's your relationship with NVIDIA been like in light of all the recent ATI press over HL2? Gabe: Valve and NVIDIA both know that we have a lot of shared customers, and we've invested a lot more time optimizing that rendering path to ensure the best experience for the most customers.