GamePC takes a look at the Intel's Core 2 Extreme X6800:

It shouldn't come to a surprise to anyone at this point, but we'll simply go ahead and say it. Intel's Core 2 Extreme X6800 is the fastest desktop processor available today, bar none. The X6800 beats AMD's top of the line FX-62 processor in every CPU benchmark, even when the FX-62 is running at overclocked speeds. In order to truly compete with the X6800, AMD would have to put out dual-core chips in the 3.6 – 4.0 GHz range, as Intel's performance per clock is quite a lot better compared to the Athlon64 X2 product line. With AMD's current manufacturing process technology, these kinds of clock speeds aren't going to come about any time soon, which means Intel will likely hold the performance crown for the foreseeable future. It's looking more and more like quad-core technology will be the savior of AMD on the desktop. However, if rumors are correct, Intel may even beat AMD to bring this technology to market as well.

Note that we said fastest "desktop" processor above. Astute readers will be aware that Intel's Xeon 5160 processor is based on the same architecture as the Core 2 Extreme X6800, and actually runs at higher clock speeds (3.0 GHz) with a faster FSB speed (1333 MHZ), but costs less (about $1000) compared to the X6800. While this may look like a staggering deal compared to the pricey Core 2 Extreme, one must keep in mind that Xeon motherboards are 2-3x more expensive compared to Core 2 motherboards, and Xeon systems also require more expensive / slower FB-DIMM DDR2-667 memory modules. Thus, as a whole, the Core 2 Extreme system will likely be a better value. Still, it's certainly interesting to think about.

Of course, having the best desktop processor on the market means that Intel can charge (more or less) whatever they want. As the $1200 to $1400 Core 2 Extreme is based on the same core architecture as the $400 Core 2 Duo E6600, it's a safe bet that Intel is making very, very good profits on these processors. If you're willing to shell out the cash, this will certainly be the best processor on the market you can buy today, but a good value it certainly is not. In terms of price / performance, the Core 2 Duo E6600 and E6700 models are far better values, and when overclocked, can deliver the same (or better) performance levels of the Core 2 Extreme X6800. However, with the X6800, you get all that performance without all the risk and worry of overclocking, and your warranties are kept intact.