Kentsfield Processors: Core 2 Extreme QX6700 and Core 2 Quad Q6600

Intel introduced the first dual-core processors on Core microarchitecture in mid summer. In fact, not so much time has passed since then, especially from the IT industry standpoint. However, Intel is ready for the next step forward: the launch of new CPUs with quad-core design based on the same Core microarchitecture!

It wasn?t that hard for Intel to introduce Core microarchitecture into the quad-core processor design. They used the same approach they worked with in the times of Presler CPU. In fact, Kentsfield is actually none other but a combination of two Conroe (Core 2 Duo) dies within the same processor package. In other words, the new quad-core Intel processor is a combination of two dual-core CPUs with Core microarchitecture.

Note that this is a very advantageous approach that makes a lot of sense. For example, it helped Intel save quite a lot on engineering and technology, which led to very early arrival of quad-core microarchitecture to the market. At the same time, Intel has also taken care of possible production issues that are typical for the early manufacturing stage of new semiconductor dies. Of course, the yields during manufacturing of two dual-core Conroe dies will be higher than in case Intel had to manufacture single dies twice as big in size and featuring about twice as many transistors.

Here I have to add two more things. Firstly, by using two dies instead of one Intel managed to save about 12% of the die size. And secondly, they got great opportunity to select the best dies for their quad-core solutions. Kentsfield is expected to utilize dies with lowest heat dissipation, which will create very attractive thermal envelope for these CPUs.

So, Kentsfield should be regarded as another CPU on Core microarchitecture that we have already discussed in detail in our article called Getting Ready to Meet Intel Core 2 Duo: Core Microarchitecture Unleashed. It boasts all the same advantages as Conroe processors with one single exception. Since the quad-core newcomer is built of two dual-core physical semiconductor dies, its L2 cache memory will consist of two 4MB parts. Each 4MB part is shared (thanks to Intel Advanced Smart Cache technology) between the corresponding pair of cores. In other words, the cores located in two physically different dies will exchange and share data in an old-fashioned manner, i.e. via the system bus and RAM.

At first, that is starting today and until the end of this year, Intel will be shipping only one Kentsfield modification aka Core 2 Extreme QX6700. This CPU will cost $999, i.e. it will be a quad-core competitor to the dual-core Core 2 Extreme X6800 processor.

The specifications of the newcomer look as follows:

If we compare Core 2 Extreme QX6700 against the top of the line dual-core processor on Core microarchitecture, we will see that Core 2 Extreme QX6700 works at 266MHz lower frequency and features 75% higher typical heat dissipation. However, both CPUs cost absolutely the same, so that the user is facing a very difficult choice between these two completely different solutions.

The diagnostic CPU-Z utility reports the following about Core 2 Extreme QX6700:

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As we see, Intel released new B3 core stepping specifically for quad-core processors: the latest Core 2 Duo core stepping is currently B2. Other than that the screenshot shows what we have expected.