Here are the vitals on the Core 2 Extreme QX6850. This processor is yet another spin on Intel's Kentsfield quad-core product, which incorporates two Core 2 Duo chips onto a single package for a quartet of bit-flipping goodness. Like other Kentsfield-based products, it has a total of 8MB of L2 cache, or 4MB per chip. The QX6850 distinguishes itself from its direct predecessor, the QX6800, with the addition of a 3GHz core clock frequency and a 1333MHz front-side bus. Intel has moved the bulk of its Core 2 lineup to this higher bus speed, whose benefits we first tested in our review of the Core 2 Duo E6750. At that time, we concluded that a 1333MHz front-side bus wasn't much help to a dual-core processor, but it might be more of a boon to a quad-core part, especially because the two chips on Kentsfield processors communicate between themselves via this bus.