MacNN reports that the 3GHz Xeon (Clovertown) processor that was introduced in the 8-core Mac Pro is a currently unannounced model.

According to comments by Intel's Bill Kircos: "We are indeed shipping a 3.0GHz Xeon version [and] expect to see faster gigahertz speeds for our high-end [Core 2] Extreme PCs very soon, too. For now, the product is in limited production and Apple has chosen to adopt it. We will introduce another 3.0GHz Xeon SKU later on as well."

Indeed, it appears Apple had waited for the 3GHz Quad-Core Xeon to become available before launching the 8-Core Mac Pro.

While rumors of an 8-core Mac Pro began back in October, the available chips at that time maxed out at 2.66Ghz. Only in March was it revealed by Intel that a 3GHz version would be coming "later this year".

It appears Apple is the first to use the as-yet unannounced 3GHz Xeon (Clovertown) chips.