HotHardware,PC Perspective and TechReport have posted their review on the long awaited B3 stepping of the AMD Phenom X4 processor:

The new AMD Phenom X4 9850 is a great processor for its segment even though it is still not able to dominate in any fashion over the Intel quad-core options. Just as with the initial 2.3 GHz Phenom B2 launch, AMD still considers the Intel Core 2 Q6600 its primary competition, and I consider the Q9450 to be another potential threat as well. This new CPU is definitely getting AMD closer to its performance goals and any enthusiast or gamer looking for a ~$240 processor is going to have a fantastic experience with the 9850. The added performance and efficiency of the 2000 MHz memory controller and system bus add to the benefits of the 2.50 GHz clock rate producing the best fastest stock speed AMD quad-core CPU to date.

The best thing I can say about the Phenom X4 9750 and 9850 is this: AMD is back in the game. The banishment of the TLB erratum to the history books is, of course, a welcome development, and the higher clock frequencies now available are a small but important step in the right direction. The Phenom X4 9850 Black Edition can't always keep pace with the Core 2 Quad Q6600 or the Core 2 Duo E8500, but it's close. AMD still hasn't caught up to Intel's 65nm "Kentsfield" processors in terms of overall performance or power efficiency, yet it has produced a credible alternative to those products. That fact, combined with aggressive pricing and the bold move of offering an unlocked upper multiplier on a $235 quad-core processor, has enabled the Phenom to grab our attention. We can finally say with confidence that if you have an existing Socket AM2 system and want to upgrade, buying a Phenom looks like a more attractive upgrade path than making the switch to Intel.