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Reviewed by: Carl Nelson [11.01.06]
Manufactured by: Intel


Sooner Than Expected

Probably the worst-kept secret in Intel's recent history, the quad-core CPU codenamed Kentsfield is here. But can you blame them for wanting to spill their guts? Not only have they pretty much embarrassed AMD with the launch of Core 2 Duo, they have doubled the amount of cores within a couple months of the initial launch. In fact, the initial launch date for this CPU was November 14th, but Intel simply couldn't wait that long, and have decided to allow us to tell you about it today, 2 weeks ahead of schedule.

A few weeks ago at IDF, Intel released some benchmarks showing how much faster their new "Core 2 Extreme QX6700" is than their previous top-dog "Core 2 Extreme X6800". Despite a lower clock speed, the Kentsfield chip showed a significant performance advantage in applications that made use of all four cores.

Obviously, benchmarks performed at a manufacturer's headquarters are to be taken with a grain of salt. Not that they are manipulated the numbers or anything; but they only allowed benchmarks to be used that they knew would show off the four core advantage.

We have put Kentsfield through a ton of real-world benchmarks, including video and audio encoding, 3d gaming, and more. And we're here to tell you whether it truly does kick ass.

Core 2 Duo Duo?

Core 2 Duo's original chip, Conroe, has both processor cores on a single die with a shared 4MB L2 cache. Previously in their dual core desktop chips such as Pentium D, they have simply taken two separate dies and used them on a single proccessor. With Kentsfield, they went back to that type of method, only this time using two dual core chips sitting on a single substrate, communicating over the Frontside Bus.

So the "Core 2 Extreme QX6700" we're looking at today is nothing more than a pair of "Core 2 Duo E6700" cores on a single chip.

This type of design is what allowed Intel to release their "Core 2 Quad" just months after "Core 2 Duo". and do so relatively cheaply. It will also make binning MUCH easier, as they will not have to try to make a wafer full of quad core dies, with 4 times the chance of something going wrong. Of course, that's not to say they don't plan on doing that in the future. In fact, it won't be too long until we start seeing 8 core processors from Intel.

There is also a disadvantage to this type of design however; the two cores have to communicate using the FSB, which currently runs at 1066 MHz. This may not leave much bandwidth for the Northbridge interconnect, but we'll see if we run into any performance problems later on.

Core 2 Extreme QX6700

As mentioned, Intel is launching Kentsfield as an "Extreme Edition" part to begin with. This CPU runs at 2.66 GHz, which is just a little bit lower than their current top CPU, the Core 2 Extreme X6800 (which runs at 2.93 GHz). Unlike prior Extreme Editions, the new model is not superceding the old one, and Intel will be providing both at the same price point. The thought is that some people may not care about having four processors in their system, and want to go for raw MHz instead. We'll find out which is a better choice later on.

Core 2 Quad

It goes without saying that Intel will be releasing more Kentsfield processors very soon, most likely in January. There is currently one model that has shown up on leaked roadmaps; the Core 2 Quad Q6600, clocked at 2.4 GHz (like the E6600). The rumoured price is $851, which is quite a bit more than a pair of E6600's which currently go for around $313. We will be including the performance results from a Q6600 by lowering the unlocked multiplier of our test CPU.

Specs & Price

Wondering how the current range of high end processors stack up against each other? Here is a table listing some of the specs. Each price is linked to a store that ACTUALLY sells the respective CPU for the listed price. The Athlon64 X2 5000+, which has been all but impossible to get until recently, is finally starting to show up in stores, albeit for higher prices than expected. As you'll see later in the review though, it may be a case of "too little, too late". We'll see soon enough.

CPU Clock Speed Bus Speed L2 Cache Process TDP Lowest Price
Core 2 Extreme QX6700 2667 MHz 1066 MT/s 2 x 4 MB 65 nm 130 W $999
Core 2 Extreme X6800 2933 MHz 1066 MT/s 4 MB 65 nm 75 W $949
Core 2 Quad Q6600 2400 MHz 1066 MT/s 2 x 4 MB 65 nm 130 W $851*
Core 2 Duo E6600 2400 MHz 1066 MT/s 4 MB 65 nm 130 W $313
Core 2 Duo E6400 2133 MHz 1066 MT/s 2 MB 65 nm 65 W $220
Athlon64 X2 4600+ 2400 MHz HT 1000 MHz 2 x 512 KB 90 nm 89 W $257
Athlon64 X2 5000+ 2600 MHz HT 1000 MHz 2 x 512 KB 90 nm 89 W $399
Athlon64 FX 62 2800 MHz HT 1000 MHz 2 x 1 MB 90 nm 125 W $689

As you can see, I put the Q6600 in italics, because as of right now it is a theoretical product. Most likely it will be exactly as shown however (although the price will probably be closer to $650-700 once it finally shows up in stores).

You'll notice that the TDP of Kentsfield is noticably higher than Conroe. That makes perfect sense of course, since it is literally a pair of Conroe chips sitting beside each other. I did some temperature measurements, running four instances of Prime95 Torture Test. The QX6700 @ 2.66 GHz got to about 57.5 degrees celsius before topping out. The X6800, running at 2.93 GHz, topped out at exactly the same temperature while running two instances of Prime 95. So it looks like Intel have managed to keep the heat down on Kentsfield, which is good; Intel wouldn't want another PressHot fiasco on their hands!

Speaking of CPU cooling, there is yet another technology being introduced to enhance power usage and heat management. In addition to C1E HALT and EIST Enhanced SpeedStep, Kentsfield chips officially introduce "DTS" or "Digital Thermal Sensor". This basically allows the motherboard to monitor the maximum temperature of each individual core much more accurately than before. This allows the fan to ramp up and down with temperature with more precision, leading to a silent operating PC. This is currently only supported by the 975 Express chipset, and some motherboards will require a BIOS update to properly cool a Kentsfield.

Kentsfield Support

Several motherboards currently on the market already officially support Kentsfield processors. In fact, all the testing done for this review was performed on a Gigabyte GA-965P-S3 motherboard (which doesn't even have an EPS 12V connector). Many boards with either a 975 or 965 chipset should work, but may require a BIOS update. In some cases, a whole new board revision is required, as is the case for Intel's BadAxe D975XBX2 motherboard. Check the manufacturer's website to make sure!

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