Product Listing

Intel Core 2 Extreme QX6700 - Quad-Core Power for Desktops

By Zachary Chan - 2 Nov 2006

The Kentsfield

Kentsfield Inside

The Kentsfield will be manufactured using existing 65nm process technology and is actually made up of two dual core Conroe cores put side by side into one processor package - a reminiscence of the older Presler design (first generation Pentium D). By using two individual Conroe dies to make the Kentsfield, Intel is able to cut down on engineering resources, maintain die yields and improve manufacturing volume. Since there is no need to redesign and qualify a whole new part, it also explains how they could ready the Kentsfield with such a short 'time to market' strategy.

Consequentially, the Kentsfield package will have doubled its transistor count to a hefty 582 million since it is physically made up of two Conroe dies. As you'd have expected, heat output will have also increased as well. Intel has tried to cap it to a max 130W TDP envelop for the QX6700, double that of the 65W TDP Core 2 Duo E6700 and matching the max TDP of the old Pentium Extreme Edition 965. Of course, we're now talking about four physical cores in a single chip, so it is still an impressive achievement. LGA775 chipsets today that support the Core 2 Duo can be upgraded to support the quad-core Kentsfield as well, most of them just requiring a BIOS update. However not all boards of this class may support it fully (especially the very low-end boards) due to the power delivery design on the board to the processor being less than optimal. While being compatible with the existing crop of Core 2 Duo motherboards means that the current 1066MHz PSB will be kept for the Kenstfield too. So, the question that begs to be asked is if the same 1066MHz PSB to the Northbridge is enough bandwidth to handle the four cores, since it will have to be split and shared between the pair of Conroe cores within.

Kentsfield package layout and features at a glance. Notice the two individual Conroe die schemas that make up the Kentsfield.

Each of the four cores will have a dedicated 64KB of L1 cache and as a whole, the Kentsfield will feature a huge combined 8MB L2 cache, but since the pair of cores aren't interconnected, each pair will only have access to 4MB, just like the Core 2 Duo. Feature-wise, there isn't a difference between the Core 2 Quad and the Core 2 Duo as the Kentsfield is basically a 2-way SMP Conroe in a chip. All the advanced features found in the Core microarchitecture are here: Wide Dynamic Execution, Smart Memory Access, Advanced Smart Cache and Advanced Digital Media Boost. For those who require a more in-depth look at the Core microarchitecture can check out our original Core 2 Duo Performance article here. The Kentsfield's thermal and power saving features include PECI (Platform Environment Control Interface) support, on-chip Digital Thermal Sensor, EIST and C1E functionality. The processor will also feature the SSSE3, EM64T, XD-bit and Virtualization (VT) technologies.

Intel Core 2 Extreme QX6700 - The first of the Kentsfield processors.

The following table clearly illustrates the detailed technical comparison between the Kentsfield and the latest dual-core processors from Intel and AMD:-

High-End Multi-Core Processors Compared
Processor Name Core 2 Extreme (quad-core) Core 2 Extreme (dual-core) Core 2 Duo (dual-core) Pentium Extreme Edition AMD Athlon 64 FX
Processor Model QX6700 X6800 E6600, E6700 965 FX-62
Processor Frequency 2.67GHz 2.93GHz 2.40GHz, 2.67GHz 3.73GHz 2.8GHz
No. of Cores 4 2 2 2 2
Hyper-Threading Technology No No No Yes -
No. of Logical Processors 4 2 2 4 2
Front Side Bus (MHz) 1066 1066 1066 1066 -
HyperTransport Bus - - - - 1GHz (2000MT/s)
L1 Cache (data + instruction) (32KB + 32KB) x 4 (32KB + 32KB) x 2 (32KB + 32KB) x 2 (16KB + 12KB) x 2 (64KB + 64KB) x 2
L2 Cache 4MB x 2 4MB 4MB 2MB x 2 1MB x 2
Memory Controller External Dual Channel (up to DDR2-800) External Dual Channel (up to DDR2-800) External Dual Channel (up to DDR2-800) External Dual Channel ( up to DDR2-667) Integrated Dual Channel (up to DDR2-800)
VID (V) 1.35 0.85 - 1.3625 0.85 - 1.3625 1.20 -1.3375 1.35 - 1.40
Icc (max) (A) - 90 75 125 90.4
TDP (W) 130 75 65 130 125
Execute Disable Bit Yes Yes Yes Yes Yes
Intel EM64T / AMD64 Yes Yes Yes Yes Yes
Enhanced Intel SpeedStep Technology (EIST) / AMD Cool 'n' Quiet Yes Yes Yes No Yes
Virtualization Technology Yes Yes Yes Yes Yes
Packaging LGA775 LGA775 LGA775 LGA775 AM2
Process Technology 65nm 65nm 65nm 65nm 90nm SOI
Processor Codename Kentsfield Conroe Conroe Presler Windsor
Die Size 286mm 143mm 143mm 162mm 230mm
No. of Transistors 582 million 291 million 291 million 376 million 227.4 million
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