Related Articles

QX6700 Extreme: Quad Core is HERE!

Finally we get to publish the "straight scoop" on Intel's new Kentsfield Core 2 Quad processor.  We spent the last few weeks with Intel's QX6700 and today we're reporting on our findings.  But first, let's talk a little about Core 2 Quad in general.

If you're not already familiar with Kentsfield, it is Intel's newest processor sporting 4 cores, aka "Core 2 Quad".  The outstanding Core 2 Duo, codenamed Conroe, of course is a 2 core part, and Kentsfield is its Quad core sibbling.

As you know, the Core 2 Duo is a true dual core CPU in that both cores are on the same physical die (leading to the "Core 2 Duo" moniker).  The Core 2 Quad takes it one step further by placing two dual core dies into the same physical processor package - that is two of the Core 2 Duo processor dies are placed side by side and connected internally, with both chips sharing the pins on the BGA 775 package.

Now why would Intel do this?

This was the quickest way of getting a four core product to market, and since the clock speed race has been side tracked into a race for more cores as a way of increasing total system performance, it was a smart temporary move until they manage to get four cores onto the same die.

The rendered image of the Kentsfield above shows how it all goes togeather - the heat spreader on top of the two dies, the two dies themselves, each measuring 143 square milimeters - and that small area holds 291 million transistors. Each of the two dies has 4MB of L2 cache shared between the two cores (per die), so there is actually 8MB of L2 cache in the package. (For more information about the Core 2 Duo architecture see our Core 2 Duo launch article)

The codename for this chip was "Kentsfield", and the first member of the Core 2 Quad family is the 2.66GHz QX6700 - which is being launched today.

(we would like to thank Intel for providing us with a QX6700 and 975X motherboard in time for us to do a launch review)

We've had the QX6700 Quad core chip in the lab for a few weeks, and have been running benchmarks essentially non-stop. Originally the launch date of Kentsfield was November 14th, but the powers that be decided to push the schedule up to Nov 1st, 9:00PM PST, so here we are.  Had the original launch date of November 14th been retained, we'd have run even more tests :-) but as it is, I think you will be happy.

Not only did we test the QX6700 at its stock speed of 2.66GHZ with a 1066MHZ FSB - we also tested it at some of the speed grades that we can expect from Intel in the near future - as well as a maximum stable overclock series of tests.

The speeds we tested at are:

• QX6700 2.66GHz 1066FSB (266x10)
• QX6800 2.93GHz 1066FSB (266x11) *1
• QX6900 3.19GHz 1066FSB (266x12) *1
• QX6700 2.66GHZ 1333FSB (333x8) *1
• QX6800 3.00GHZ 1333FSB (333x9) *1
• QX6950 3.33GHZ 1333FSB (333x10) *2
• QX MAXED OUT (you'll have to read the article to find out)

Note 1: Intel has not released or endorsed these names or specifications, they are educated guesses based on the Core 2 Duo naming scheme.

Note 2: It would not make sense to label a 3.33GHz processor with the same number as a 3.19GHz processor, so I cut the difference in half.

During the recent Intel Developer's Forum, Intel had a presentation on Kentsfield - A quick review of some of the slides from that presentation will yield some insight into this new chip.

As you can see, they are making basically the same points as they did during the Core 2 Duo launch - this makes sense, as Kentsfield is simply two Core 2 Duo processors packaged in one BGA (Ball Grid Array) processor package.

Intel's slides promise a massive 70% greater performance over the X6800 Extreme processor, and today we're here to explore just what Kentsfield means for the enthusiast and corporate users and figure out whether or not Intel can deliver on this promise.

Frankly, its not possible for them to deliver 70% across the board. It is logically impossible.

If you have a single threaded application, and it is the only process running, the X6800 will be up to 10% faster, simply based on its 2.93GHz clock rate versus the QX6700's 2.66GHz clock rate. There is no magic to this, simply logic.

For performance improvement, we have to look at multi-threaded applications; and to a lesser extent, the "snappyness" of the system under load, when there are several applications running. Unfortunately, "snappyness" is difficult to quantify, as it is a subjective experience, so we will basically stick to benchmarking software - where we can measure the speed increases (if any).

Intel realizes this - and provided a slide showing some of the vendors of applications that can take advantage of the Core 2 Quad.

Intel DID however deliver on their promise to have Kentsfield launched in November, and the part is expected to be available for sale around middle of the month (Intel says on the 14th).

Before we get to the testing and technical details, I'd like to discuss why you should care about quad core processors.

I mean, let's be real - dual core processors have only really become popular in the last year, and already we have a quad core offering from Intel, with AMD trying to launch a quad core device by Q2 2007... why should we care?

Reason #1: SPEED!

Reason #2: MARKETING

Reason #3:  MULTIMEDIA

Reason #4: VIRTUALIZATION

Reason #5: POWER SAVINGS

Reason #6: CHEAPER DUAL CORE PROCESSORS!