TheTechLounge posted a review on the Diamond Radeon HD 4870 1GB

I don't think there's a stock 4830. Sapphire usually runs that route with the non-Toxic or their other variants, but I'm pretty sure that it's up to the board partner to build a better 4830; they're all different. Each has its own heatsink and board layout. Sapphire's is, at least, true to the namesake, and mega-blue.

Diamond Radeon HD 4870 1GB Review