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Inside the Pentium D 805

12:26 - Wednesday 10 May 2006 by Tom's Guide Team

The Pentium D 805 is based on the first Intel dual core processor, the Pentium D with the Smithfield core. Its predecessors in this family were rated at clock speeds of 2.8 GHz (D 820) to 3.2 GHz (D 840). Both cores in this CPU family come equipped with a 1 MB L2 cache, whereas the most current dual core processors in the 900 series make 2 MB available to each core. For the last year, Intel has brought no new models in the 800 series to market, because the company has switched its fabrication from a 90 nm process to a 65 nm one in the meantime, and has used this smaller building block size only for processors in the 900 series. But then out of nowhere, the old Smithfield core put in another appearance in the form of the Pentium D 805.

The Intel Pentium D 805 costs only £79.95 but incorporates a dual core - only a few users were in the know about this.

A rear view of the Pentium D 805, built for the LGA 775 socket.

Processor	Number	Clock Speed	L2 Cache	Multiplier	FSB clock
Pentium EE	965	Dual 3724 MHz	2 MB	14x	266 MHz QDR
Pentium EE	955	Dual 3466 MHz	2 MB	13x	266 MHz QDR
Pentium D	950	Dual 3400 MHz	2 MB	17x	200 MHz QDR
Pentium D	940	Dual 3200 MHz	2 MB	16x	200 MHz QDR
Pentium D	930	Dual 3000 MHz	2 MB	15x	200 MHz QDR
Pentium D	920	Dual 2800 MHz	2 MB	14x	200 MHz QDR
Pentium 4 "E"	661	Single 3600 MHz	2 MB	18x	200 MHz QDR
Pentium 4 "E"	651	Single 3400 MHz	2 MB	17x	200 MHz QDR
Pentium 4 "E"	641	Single 3200 MHz	2 MB	16x	200 MHz QDR
Pentium 4 "E"	631	Single 3000 MHz	2 MB	15x	200 MHz QDR
Pentium EE	840	Dual 3200 MHz	1 MB	16x	200 MHz QDR
Pentium D	840	Dual 3200 MHz	1 MB	16x	200 MHz QDR
Pentium D	830	Dual 3000 MHz	1 MB	15x	200 MHz QDR
Pentium D	820	Dual 2800 MHz	1 MB	14x	200 MHz QDR
Pentium D	805	Dual 2666 MHz	1 MB	20x	133 MHz QDR

By comparison with all the other processors in this series, the D 805's relatively low clock speed of 2.66 GHz doesn't make much of an impression on store shelves. At 133 MHz (533 QDR), its front side bus clock rate is laughable when compared to state-of-the-art CPUs with 200 and 266 MHz speeds.

FSB clock	Bandwidth
266 MHz (1066 QDR)	8.53 GB/sec
200 MHz (800 QDR)	6.40 GB/sec
133 MHz (533 QDR)	4.20 GB/sec

Out of the box and with no additional modifications, the Pentium D 805 is not even half as fast at exchanging data with the Northbridge chipset, when compared to leading-edge CPUs with 266 MHz FSB clocks.