AMD's latest Phenom processors offer solid performance at a mid-range price, with the added bonus of lower power draw.

AMD's latest Phenom CPUs are fast, but not the fastest chips around. That distinction falls to Intel's Core series of CPUs, which are 5 to 10 percent speedier, clock cycle for clock cycle. Still, the new units - the Phenom X4 9950 Black Edition, the Phenom X4 9350e, and the Phenom X4 9150e processors - cost less than Intel's most recent chips.

The high-end Phenom X4 9950 Black Edition (CPU only) compares well, price-wise, with Intel's quad-cores, especially the newer 45-nanometer-process Q9550, Q9450, and Q9300.

Performance-wise, though, it's more comparable to Intel's 65nm Core 2 Quad Q6600 and Core 2 Quad Q6700. The 65nm Phenom X4 9950 provides a 4 percent speed increase (2.6GHz, up from 2.5GHz) over the previous flagship product, the 9850. The Black Edition CPUs, like Intel's Extreme models, allow you to increase the clock multiplier. Most CPUs are locked at a fixed multiple of the frontside bus--for instance, 12X with a 200-MHz bus, or 2.4GHz. The Phenom X4 9850 will now be available only in a cheaper, locked version.

All three new AMD chips use what the company refers to as B3 silicon, with a slight revision of AMD's original Opteron/Phenom design that eliminates a potential problem that reportedly could lock the CPU under a heavy virtualization load. AMD claims there were no reports of the problem ever occurring in a desktop PC; but as soon as the problem was reported, motherboard vendors implemented an optional BIOS fix at AMD's behest.

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