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Intel's Solution

Starting in May 2004, Intel officially began creating new processor model numbers for existing and forthcoming processors. Within a given processor family, the processor model numbers are supposed to help a potential buyer figure out how processors compare to each other.

To put it mildly, I'm not a fan of this idea. As you may know from reading Upgrading and Repairing PCs, 15th Anniversary Edition or my articles "Athlon XP Barton", and "AMD Athlon XP - Xperience Performance Beyond the Gigahertz Rating", I don't like chip names based on performance ratings or other schemes such as the old Cyrix or current AMD Athlon XP processors use. Although Intel isn't trying to compare its processors to another brand with these processor numbers, how a particular processor number is determined is anything but simple.

According to Intel's official "Intel Introduces Processor Numbers Page", the following factors are used to create a processor number:

  • Architecture

  • Cache size

  • Clock Speed (GHz)

  • Front Side Bus speed

  • Other Intel technologies

That's a wide variety of factors to create a processor number. In the real world, what does it mean?

Interpreting Processor Numbers

The first Intel processors to receive processor numbers using this new scheme are mobile processors.

Table 4 lists the processor families and numbering schemes used for mobile processors, while Table 5 lists the processor families and number schemed used for desktop processors.

Table 4 – Mobile Processor Model Number Groupings

Processor Model Number

Processor Families

7xx

Pentium M (includes low-voltage and ultra low-voltage versions)

5xx

Mobile Pentium 4 (includes versions with HT Technology and Hyper-Threading Technology support)

3xx

Celeron M (includes ultra low-voltage versions)


Table 5 – Desktop Processor Model Number Groupings

Processor Model Number

Processor Families

5xx

Pentium 4 (includes versions with HT Technology and Hyper-Threading Technology support)

3xx

Celeron D


Figure 1 shows how the processor name contains the processor family and the processor number.

Figure 1Figure 1 The processor name is created from the processor family and the processor number.

To see how the processor numbers work in practice, let's look at two examples. First, here's how the first Pentium M processors with model numbers compare to each other as shown in Table 6.

Table 6 – Intel Pentium M Processor Numbers Compared

Processor Number

Clock Speed

L2 Cache Size

FSB Speed

Process Technology

755

2.0GHz

2MB

400MHz

.09 micron

745

1.8GHz

2MB

400MHz

.09 micron

735

1.7GHz

2MB

400MHz

.09 micron


The reason for the processor number differences in Table 6 is clear: faster clock speed. Other major factors are the same. What happens when processors with two or more differences are numbered? Table 7 compares a few Pentium 4 processors with similar clock speeds but other differences in design.

Table 7 – Intel Pentium 4 Processor Numbers Compared

Processor Number

Clock Speed

L2 Cache Size

FSB Speed

Process Technology

518

2.8GHz

1MB

533MHz

.09 micron

520

2.8GHz

1MB

800MHz

.09 micron

530

3.0GHz

1MB

533MHz

.09 micron

532

3.06GHz

1MB

800MHz

.09 micron


In the processors listed in Table 7, the difference between the 518 and the 520 is the FSB (the 520 is faster), while the 532 has a faster clock speed and faster FSB than the 530. As you can see from these examples, more than the clock speed is involved in determining a processor number.

Note that neither example compares different processor families. That's because Intel's processor numbering system is not designed to facilitate comparisons between different types of processors. So, if you're not sure whether to get a Celeron with a faster clock speed or a Pentium 4 with a slower clock speed, don't expect the processor number to help you. To me, this makes the processor number system a lot less useful than it could be.

Keeping Track of Processor Numbers

It will take some time for Intel to switch to the processor number system for current and forthcoming processors. It's likely that older models in a particular processor family, particularly those which are no longer being produced, will not receive processor numbers. To see which mobile and desktop processors have been assigned model numbers, check this Intel web page often: http://www.intel.com/products/processor_number/info.htm

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