The History

The First Steps Towards Mainstream

Overclocking goes further back than the Celeron 300A. Back in the day 486s, 386s, and even 286s were all pushed beyond their specifications by people hoping to get some more speed out of them. Of course, back then, overclocking was still truly experimental. There was no SoftMenu III, and more likely than not, the jumper settings on your motherboard were completely undocumented. Some boards required a bit of soldering or makeshift jumpers to short out the proper settings, so burning out your CPU was a definite possibility.

The first big steps towards overclocking were made in the Pentium era. During this time, typical neighborhood techies discovered that a Pentium 75 was nothing more than an underclocked Pentium 90. Soon, people were taking Pentium 133s and turning them into 166s, and in turn 166s soon became 200s. When the 233MMX made an entrance, it soon became obvious that the chip had little trouble reaching 250MHz or 266MHz.

The Breakthrough

Overclocking didn't become a "mainstream" activity until the introduction of the Celeron 300A. When the 300A was first released, early tests revealed that most 300A chips could get to 450MHz with very little trouble. Some processors needed a bit of extra cooling, others a slight bump in voltage, but the success rate was fairly high. The 50% speed increase made the 300A the choice chip for overclockers around the world.

The next big overclocking chip was the Celeron 366, which offered an even larger gain than the 300A's 150MHz. The 366 jumped up 183MHz to reach 550MHz. The success rate wasn't quite as astounding, and fewer overclockers tried it since many already had 300As, but it was still a monster of a bargain. Today we're seeing promising chips like the P3-550E and P3-600E.

Several Factors

In this guide, we'll cover the factors that affect a CPU's overclockability. The main three, which are most influential on potential speeds are:

Binning: Why would Intel release the Celeron 300As at only 300 when they could so easily reach 450? We'll explain why Intel and AMD actually clock chips below their highest possible speeds.

Steppings: The first batch of processors usually don't overclock as well as later batches, and we'll explain why.

Manufacturing process: Just like .25 micron chips have a much higher speed limit than their .35 micron cousins, the new generation of .18 micron CPUs have a higher limit than the .25s.