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Intel Pentium III

Intel Pentium III: Image courtesy of Intel Corporation

533(B) & 600(B)


Stop Press!

A major UK based OEM has informed us that Intel has pulled back on the launch of the Pentium III(B) with major system integrators until the i820 is available. The suggested release date is October 25, which is the scheduled release date of the Coppermine Pentium III.


The summer of 1999 has seen a flurry of activity from the two main CPU manufacturers Intel and AMD. The intense rivalry between Intel and AMD has seen Intel push its Pentium III line of processors all the way through 550 and 600 MHz. Raw speed though is not the only part of Intel's strategy for the future. In order to be competative Intel has had to enhance its ageing P6 core (it has been around since the Pentium Pro 133 in late 1995), by adding 256 Kb level 2 cache on chip and running at full clock speed (again this is a similarity to the Pentium Pro, but it is now much easier to implement), supported by the new i820 chipset.

It became apparent during 1999 that Intel would not be able to meet its June launch date for Coppermine and i820, so a number of stopgap measures were needed to stave off pressure from AMD with its new and impressive Athlon processor. Thus the original Katmai Pentium III core was pushed to 550 and later 600 MHz. Coppermine and i820 were due to debut on Monday September 27, but as the date approached Intel realised that Coppermine would not be ready for the launch and so a compromise was needed in order to create a market for the i820 with its 133 MHz Front Side Bus. To meet this need, the Intel Pentium III 533(B) and 600(B) were born.

As is apparent now, Intel has had to postpone the launch of the i820 due to data integrity problems associated with running 3 Rambus RIMM sockets, and so the new Pentium III 533(B) & 600(B) processors are only supported by the new budget i810e chipset, which features an integrated i752 graphics controller, hardly something which can be described as high end. The other options are to overclock the existing BX chipset, or to use VIA's Apollo Pro 133.

So what are the new Pentium III 533(B) and 600(B) processors? Well, they both feature the same 0.25 micron Katmai core as existing Pentium III processors, with 512 Kb level 2 cache, running at 1/2 speed on the processor module. The main difference is that both chips run on a 133 MHz Front Side Bus as opposed to 100 MHz with existing Pentium III's. These chips are not Coppermine Pentium III's as has been mistakenly believed in some parts of the Internet. These chips are distinguishable from ordinary Pentium III chips by the addition of a "B" suffix after the MHz rating. The "B" is used to indicate a 133 MHz bus. Coppermine Pentium III's will be distinguishable by an "E" suffix. The entire scheme will look like this:

B. This is for 0.25 micron Pentium III chips running on a 133 MHz bus.

E. This is for 0.18 micron Coppermine Pentium III chips with 256 Kb on chip cache running on a 100 MHz bus.

EB. This is for 0.18 micron Coppermine Pentium III chips with 256 Kb on chip cache running on a 133 MHz bus.

Overall performance of the Pentium III(B) is similar to that of equivalently clocked Pentium III processors, but with improvements being found in areas such as memory transfer and AGP due to the increased bus speed. Overall though, the increases are too small to be noticable in comparision with 100 MHz bus Pentium III chips.

Pentium III 533(B) & 600(B), the verdict.

Like other Katmai Pentium III processors running at speeds over 500 MHz, we at the Processor Emporium are slightly ambivalent about the latest Pentium III(B) processors. The Katmai core was never intended to run above 500 MHz as this was meant to be Coppermine territory. Roadmaps 6 months ago had the 533 MHz part as a 0.18 micron Coppermine, not a 0.25 micron Katmai, so we feel that higher clock speeds on the P6 core need to be Coppermine's. Intel has done exceptionally well to ramp Katmai all the way to 600 MHz, but Coppermine is needed by Intel if it is to keep touch with AMD's Athlon.

With the launch of the i820 chipset postponed, the reasoning behind the Pentium III 533(B) & 600(B) has now disappeared. The options for running the PIII(B) are now with the i810e chipset, an overclocked BX or with VIA's Apollo Pro 133 chipsets. The main reason for the PIII(B) was to support i820. This now looks likely to co-incide with the launch of the Coppermine, which in our opinion is a much better bet than the PIII(B).

Pentium III 600.

Pentium III (E & EB).

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