AMD introduced two new high-end Socket AM3 processors today; the 3GHz Phenom II X4 945 and the 3.2GHz Phenom II X4 955 Black Edition. Both are quad-core chips with a TDP of 125W, the 945 has a MSRP of $225 while the 955 BE costs $20 more.
Lets take a look at two reviews to see how these new chips perform, first up is the test from The Tech Report. They conclude the 955 is basically a mirror image of Intel's Core 2 Quad Q9950:
AMD knew what it had in this CPU: practically a mirror image of the Core 2 Quad Q9550. They've done two smart things, as a result. They've priced the chip right and have given it an unlocked multiplier to simplify overclocking. Add to those things the fact that Socket AM3 seems to have a better upgrade path than LGA775, and the Phenom II X4 955 looks to be the smarter choice for most consumers, should they be choosing between these two products.
Another nice review can be found at AnandTech, they also conclude the performance of this chip is similar to the Q9550 and that the AM3 platform is more future proof than Intel's LGA775. However, those looking for a bit more performance might considering spending an extra $100 to get a Core i7 920 based system.
From a longevity standpoint, the AM3 platform is much wiser to invest in than LGA-775. Intel has already shown all of its cards there, and there aren't going to be any faster Core 2 Quads - just cheaper ones. By the end of this year Intel will begin transitioning to LGA-1156 and 775 will start fading away. By contrast, AMD's Socket-AM3 is going to be the flagship for the company for all of 2009 and it'll continue to live on into 2010. If you're choosing between Socket-AM3 and LGA-775, AMD has made that choice very easy - Phenom II is the way to go if you're concerned about a long term upgrade path, not to mention that the chips are generally cheaper than their Intel equivalents.