The key things to take from today's look at the 4800+ is that it's generally no slower, but generally no faster either, than an FX-53 in single-threaded tests, yet it'll cost you a fair bit more. I hope it's obvious that a dual-core processors benefits lie elsewhere, with multi-threaded applications and real-world operating system usage. Think HyperThreading.
That the new CPUs will work fine in existing Socket 939 boards that support Athlon FX-53 and Athlon FX-55, with just a change in BIOS and without any change in cooling needed (if you have an Athlon FX-55 PIB cooler, or something aftermarket that's rated to handle that CPU) is all the better.
http://www.hexus.net/content/reviews...lld19JRD0xMTcw