XSReviews has reviewed the Sapphire 2600 Pro AGP 512MB
A quote from the article:
Sapphire 2600 Pro AGP 512MB Review
Sapphire don't mess with the green camp; they're ATI through and through. This means that they don't just deal with the high end cards though, it also means they cover mid-range and budget cards, even old technologies like AGP. Today we have the 2600 Pro 512mb from Sapphire on an AGP platform. How does it compare to our P4's old favourite, the x1950 Pro? Let's see.
Sapphire 2600 Pro AGP 512MB Review