Kentsfield (microprocessor)

Kentsfield

Intel Core 2 Quad Kentsfield Q6600
Produced	From 2006 to 2009
Max. CPU clock rate	2133 Mhz to 3000 Mhz
FSB speeds	1066 MT/s to 1333 MT/s
Instruction set	x86-64
Microarchitecture	Core
CPUID code	06Fx
Product code	80562
Cores	4
L2 cache	2x4 MiB
Socket(s)	LGA 775
Application	Desktop, UP Server
Brand name(s)	Core 2 Quad Q6xxx Core 2 Extreme QX6xxx Xeon 32xx

Kentsfield is the code name of the first Intel desktop quad core^[1] CPU branded Core 2 (and Xeon for lower-end servers and workstations), released on November 2, 2006. The top-of-the-line Kentsfields were Core 2 Extreme models numbered QX6xx0, while the mainstream ones branded Core 2 Quad were numbered Q6xx0. All of them featured two 4 MB L2 caches. The mainstream Core 2 Quad Q6600, clocked at 2.4 GHz, was launched on January 8, 2007 at US$851 (reduced to US$530 on April 7, 2007). July 22, 2007 marked the release of the Q6700, and Extreme QX6850 Kentsfields at US$530 and US$999 respectively along with a further price reduction of the Q6600 to US$266.^[2] Both Kentsfield and Kentsfield XE use product code 80562.

Variants

Processor	Brand name	Model (list)	Cores	L2 Cache	Socket	TDP
Kentsfield	Xeon	32xx	4	2x4 MiB	LGA 775	95-105 W
Kentsfield	Core 2 Quad	Q6xxx	4	2x4 MiB	LGA 775	95-105 W
Kentsfield XE	Core 2 Extreme	QX6xxx	4	2x4 MiB	LGA 775	130 W

Kentsfield

Analogous to the Pentium D branded CPUs, the Kentsfields comprise two separate silicon dies (each equivalent to a single Core 2 duo) on one MCM.^[3] This results in lower costs but lesser share of the bandwidth from each of the CPUs to the northbridge than if the dies were each to sit in separate sockets as is the case for example with the AMD Quad FX platform.^[4] Also, as might be predicted from the two-die MCM configuration, the max power consumption (TDP) of the Kentsfield (QX6800 - 130 watts, ^[5] QX6700 - 130 W, ^[6] Q6600 - 95 W ^[7]) has been found to be double that of its similarly clocked Core 2 Duo counterpart.

The multiple cores of the Kentsfield most benefit applications that can easily be broken into a small number of parallel threads (such as audio and video transcoding, data compression, video editing, 3D rendering and ray-tracing). To take a specific example, multi-threaded games such as Crysis and Gears of War which must perform multiple simultaneous tasks such as AI, audio and physics benefit from the quad-core CPUs.^[8] In such cases, the processing performance may increase relative to that of a single-CPU system by a factor approaching the number of CPUs. This should, however, be considered an upper limit as it presupposes the user-level software is well-threaded. To return to the above example, some tests have demonstrated that Crysis fails to take advantage of more than two cores at any given time.^[9] On the other hand, the impact of this issue on broader system performance can be significantly reduced on systems which frequently handle numerous unrelated simultaneous tasks such as multi-user environments or desktops which execute background processes while the user is active. There is still, however, some overhead involved in coordinating execution of multiple processes or threads and scheduling them on multiple CPUs which scales with the number of threads/CPUs. Finally, on the hardware level there exists the possibility of bottlenecks arising from the sharing of memory and/or I/O bandwidth between processors.

Kentsfield XE

The first Kentsfield XE, named Core 2 Extreme QX6700 (product code 80562) and clocked at 2.67 GHz, was released on November 2, 2006, at US$999.^{[10][11][12][13][14]} January 4, 2008, marks its discontinuation.^[15] It featured the Kentsfield XE core, and complemented the Core 2 Extreme X6800 dual-core processor based on the Conroe XE core. Like their dual core Extreme predecessors, CPUs with the Kentsfield XE core had unlocked multipliers.

The Core 2 Extreme QX6800 clocked at 2.93 GHz was released on April 8, 2007, at US$1,199. It had a 130 W TDP thermal envelope, and was intended for high end OEM-only systems.^[16]

The Core 2 Extreme QX6850 clocked at 3.0 GHz was launched on July 22, 2007, at US$999. It featured a faster 1333 MT/s FSB. Simultaneously, the previously available Extreme QX6700 was reduced in price.

Related processors

The dual-core desktop version of Kentsfield is Conroe, the server versions of Kentsfield are the dual-processor Clovertown (Xeon 53xx) and the multi-processor Tigerton (Xeon 73xx).

Successor

Kentsfield was subsequently replaced by the 45 nm Yorkfield processor.

References

1. "Intel Clovertowns step up, reduce power". TG Daily. Retrieved 2007-09-05.
2. "Intel Q3's Prices Revealed: 70% off to Intel C2Q Q6600". HKEPC Hardware. Retrieved 2007-03-16.
3. "Intel Kentsfield Preview". X-bit labs. Retrieved 2006-09-29.
4. "AMD's Quad FX platform: AMD decides to socket to 'em". The Tech Report. Retrieved 2007-06-11.
5. "Overindulge Yourself with QX6800: Not Your Plain Vanilla System!". Tom's Hardware. Retrieved 2007-06-11.
6. "Intel quad-core QX6700 reaches system builders". TG Daily. Retrieved 2007-06-11.
7. "Intel pushes Q6600 quad-core CPU into 95 watt systems". TG Daily. Retrieved 2007-06-11.
8. "Crysis - Confirmed Runs Best on Quad Core and 64 Bit OS". Tom's Hardware. Retrieved 2007-08-28.
9. "No Quad Core Scaling in Crysis?". Extreme Tech. Retrieved 2008-03-09.
10. "Intel's Core 2 Extreme QX6700: The Multi-core Era Begins". AnandTech. Retrieved 2006-11-11.
11. "Intel Core 2 Extreme QX6700". Bit-Tech. Retrieved 2006-11-11.
12. ""Kentsfield" to Debut at 2.66 GHz". DailyTech. Retrieved 2006-09-29.
13. "The Quad Squad". CNET. Retrieved 2006-11-12.
14. "Intel "Kentsfield" Named Core 2 Quad". DailyTech. Retrieved 2006-09-29.
15. "Intel already phasing out first quad-core CPU". TG Daily. Retrieved 2007-09-07.
16. "Overindulge Yourself with QX6800: Not Your Plain Vanilla System!". Tom's Hardware. Retrieved 2007-06-11.