The browser version you are using is not recommended for this site.
Please consider upgrading to the latest version of your browser by clicking one of the following links.

Support

Intel® Pentium® 4 Processor Speed Letter Designators A, B, C, and E


Last Reviewed: 24-Oct-2016
Article ID: 000007235

What do the letters after the processor speed mean?

Intel® Pentium® 4 Processors that share the same core speed in GHz may have different product features. In cases where different processors exist at a single speed, letter designators are added to the processor core speed. Distinguishing features include the size of the L2 Advanced Transfer Cache, speed of the front side bus, and type of manufacturing process used.

'A' designator:
The 'A' designator identifies Pentium 4 processors with 512KB full speed L2 Advanced Transfer Cache. For example, the Pentium 4 processor at 2 GHz has 256 KB L2 cache while the Pentium 4 processor at 2A GHz has 512 KB L2 cache.

'B' designator:
The 'B' designator identifies Pentium 4 processors that support a 533 MHz front side bus speed. For example, the Pentium 4 processor at 2.40 GHz supports a 400 MHz bus speed and the Pentium 4 processor at 2.40B GHz supports a 533 MHz bus speed.

'C' designator:
The 'C' designator identifies Pentium® 4 processors that support Hyper-Threading Technology and an 800 MHz front side bus. For example, the Pentium® 4 processor at 2.40C GHz supports an 800 MHz front side bus and Hyper-Threading Technology.

 
Note The letter 'D' is not used at this time.
 

'E' designator:
The 'E' designator identifies Pentium® 4 processors that are manufactured using the 90 nanometer process with 1MB L2 Advanced Transfer Cache.

Exception:
The Pentium® 4 processor at 2.80A GHz is one exception. In this case, the 'A' designator indicates a Pentium® 4 processor at 2.80 GHz with 1 MB L2 cache, 533 Mhz front side bus built using 90 nanometer process. This processor does not support Hyper-Threading Technology.

No designator:
If no letter designator is present, then there is no overlap in process technology or front side bus speed at that processor core speed. For example, all Pentium 4 processors at 3.06 GHz are built using the 0.13 micron process technology and support a 533 MHz bus speed. Therefore, no letter designator is indicated.

This article applies to: