The original Celeron was terrible. Because of no L2 cache present, its performance was less than tolerable. Thus, Intel decided to launch Celeron A, which was different from the original Celeron on its L2 cache with 128KB running at the processor speed. Actually, Celeron A was the first processor for PCs to have a L2 cache integrated in the processor.

The first version of Celeron A worked with a clock of 300 MHz. In order to differentiate from the original Celeron of 300 MHz (with no L2 cache), Intel added the letter ”A“ after the number. Therefore, the Celeron A 300MHz version is known as 300A.

Figure 2: Detail of the Celeron 300A marking, with 128KB on-die L2 cache.

Main features of Celeron A were:

• Based on Pentium II with Deschutes core
• Manufacturing process: 0.25 μm
• L1 cache: 32 KB total, 16 KB for instructions and 16 KB for data
• L2 cache: 128 KB
• External clock rate: 66 MHz
• Packaging: SEPP
• Socket: Slot 1

Available models of Celeron A are listed on the chart below. TDP stands for Thermal Design Power and indicates the CPU maximum thermal dissipation.