WHAT CAN I SAY about the Pentium 4 Extreme Edition processor? It's a stranger in a strange land, an anomaly in the desktop processor world, a thousand-dollar CPU inhabiting a world of sub-$1K computers. The technology comes from the Intel's high-end server products, a Xeon processor core, dubbed Gallatin, with 2MB of on-chip L3 cache.

Le-vel-three.

That's in addition to the L1 and L2 caches you'll find on normal Pentium 4s. Not only that, but the Extreme Edition is based on older technology; the Gallatin core is derived from the Pentium 4 "Northwood" design that powered the P4's successful run between 2GHz and 3GHz over the past couple of years. Newer P4s are based on the 90nm "Prescott" core, a substantially redesigned processor that offers higher performance in some cases and lower in others.

Intel today is launching a new version of the Pentium 4 Extreme Edition, and because it's not based on the Prescott core, it lacks certain new features, such as support for SSE3 instructions. What it does have, however, is one very important attribute: the ability to run on a 1066MHz bus. The new P4 Extreme Edition's partner in crime is the Intel 925XE Express chipset, a slightly tweaked version of the 925X Express chipset that also allows for a 1066MHz front-side bus, up from 800MHz. This faster bus should remove a key bottleneck, allowing the CPU to talk to dual channels of 533MHz DDR2 memory with the benefit of symmetry. (533MHz times two, you see, is 1066MHz. Clever, no?)

The big question about this new Extreme Edition processor is whether a faster bus alone can bring its performance into truly extreme territory. The new CPU runs at 3.46GHz, only up 66MHz from the 3.4GHz version that preceded it. Well, OK, 66.6666666666667MHz, to be exact. In our last CPU review, the Extreme Edition 3.4GHz was exposed like Ashlee Simpson on SNL. The regular ol' Pentium 4 560 at 3.6GHz—a product that costs less than half the price—often outperformed the Extreme Edition 3.4GHz, and AMD's range of Athlon 64 processors absolutely embarrassed the Pentium 4s in our gaming tests. Doom 3 was playing, but the P4's lips weren't moving. Can the Extreme Edition's massive cache, fast DDR2 memory, and a faster system bus restore some of the luster to Intel's flagship product? We're about to find out.