What is the difference between an Intel Pentium III and an Intel Celeron processor?
Celeron refers to a line of processors from Intel. They are
low-cost counterparts of Pentium II, III, 4, M, and D processors.
They differ mainly in the amount of L2 cache. Celerons have a
smaller L2 cache, which is basically a buffer in the CPU to avoid
slowdown. With a smaller L2 cache, Celerons perform slightly worse
in some processor-intensive applications.