You might not be able to tell by checking AMD's website, but the company has just added a new graphics card to its mainstream lineup: the Radeon HD 4830. This offering effectively bridges the gap between the $160+ Radeon HD 4850 and the $80 Radeon HD 4670, and it's available right now.
Newegg already has HIS, PowerColor, and Sapphire variants of the 4830 in stock, and it's selling them for $129.99 before shipping. Each model features 640 stream processors, a 575MHz core clock speed, 512MB of 900MHz GDDR3 RAM (that's an "effective" 1800MHz), and a 256-bit memory interface. By contrast, the vanilla Radeon HD 4850 has 800 SPs, a 625MHz core speed, and a 993MHz memory speed. Those perks will cost you at least $30 more before any rebates, though.
Of course, the big question isn't how the newcomer compares with the Radeon HD 4850, but how well it stacks up against the similarly priced GeForce 9800 GT from Nvidia. We're working diligently on a review in order to answer that question (among others), so stay tuned!