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Getting Your Hands on an Execute Disabled Bit Processor

As of the first quarter of 2005, Intel had three distinct families of Pentium 4 processors: the Pentium 4 Extreme Edition, Pentium 4 with Hyper-Threading Technology and Pentium 4. There are four types of Intel desktop processors within these families that support Execute Disabled Bit:

  • 3.73GHz Pentium 4 Extreme Edition
  • All 600-series Pentium 4
  • 5xxJ-series Pentium 4
  • 3xxJ-series Celeron D

Because the 5xx Pentium 4 and 3xx Celeron D processor families also include processors which don't feature Execute Disable Bit, let's take a closer look at these two processor families.

The J-Series Difference for Pentium 4: Buffer-Overflow Protection

You can purchase two variants in the 500 series: those marked 5xx and those marked 5xxJ. Processor numbers including J in their model number identify processors which include Execute Disable Bit, making them a more desirable purchase than the non-J processors. Be sure to look for J in the processor number when you purchase a processor or a system in Intel's 500 series.

As time goes on, it's likely that all 5xx-series processors will include Execute Disable Bit. For example, the new 570J (Socket 775, 1MB L2 cache, 3.80GHz, Execute Disable Bit) does not have a non-J counterpart.

Celeron D Processors – the J-Series Differences

The Celeron D processor family is based on the Pentium 4 in 90-namometer process, but offers smaller L2 cache sizes, lower clock speeds, no support for HT Technology, and slower front-side-bus (FSB) speeds. Intel also uses processor numbers for the Celeron D, and all current models are numbered in the 300-series range.

J-series Celeron D processors, like their Pentium 4 J-series counterparts, include Execute Disable Bit, but also support Socket 775. For example:

  • Intel Celeron D processor 345 uses Socket 478
  • Intel Celeron D processor 345J uses Socket 775 and supports Execute Disable Bit

Execute Disable Bit – Who's In, Who's Out

All four Intel desktop processor families which include Execute Disable Bit are built using the latest Socket 775 (LGA-775) form factor. As Intel continues to phase out Socket 478, it's apparent that owners of existing Socket 478 systems will need to replace their systems or at least the motherboards and processors to reap the security benefits of Execute Disable Bit.

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