I’m sure you have seen the ads for all the new pc with all the vacant processors from Pentiums to Celerons to AMDs. Intel offers 2 main types of CPUs for desktop/workstation pc, the Pentium 4 and the Celeron. I’m also sure having noticed that the Celerons are cheaper than the Pentium 4s. Here is the reason why.

Smaller cache memory

Cache is fast memory that is attached to the CPU that contain the most recently used data. Celeron chip have less memory than Pentium 4 chips. A Celeron naturally has 128 or 256 kilobytes of L2 cache, while a Pentium 4 can have up to 2 MB of cache. The amount of L2 cache memory makes a big variation on performance.

Clock speed

Cache is fast memory that is attached to the CPU that contain the most recently used data. Celeron chip have less memory than Pentium 4 chips. A Celeron naturally has 128 or 256 kilobytes of L2 cache, while a Pentium 4 can have up to 2 MB of cache. The amount of L2 cache memory makes a big variation on performance.

Bus speed

Bus rate is the speed at which the data on the motherboard moves. Celerons have bus speeds up to 400 MHz while Pentium now have up to 1066 MHz bus speed
Pentium 4s also offer skin like Hyper Threading Technology which allows multiple threaded application to run concurrently which makes one physical CPU appear as two logical CPUs to increase performance.