Intel Celeron 533

The Celeron CPU has been known for quite some time to be an excellent overclocker.  The reputation came mainly because of the overclocking successes provided by the original Celeron 266 and especially the Celeron 300A.  In fact, users are still using their $100 Celeron 300A CPUs running at a lofty 450MHz with little more than a decent heatsink/fan combo and some thermal grease. 

The reason for the better than average overclocking potential of the earlier Celeron CPUs was because Intel’s yields on the 0.25-micron process were so great that they reached close to the potential of the process very early on.  We already indicated that the potential of the process was around 600MHz (of course there will be some successes that occur beyond and below this mark), and as time went on we noticed that more and more CPUs were able to be overclocked to around that 600MHz mark.

After the Celeron 300A at 450MHz craze, the next big hit was the Celeron 366 running at 550MHz.  The success rate of these 366s at 550MHz grew to be so high that it was almost absurd to hear about a 366 that wouldn’t hit 550MHz, and you’d hear cries of agony when a user would end up with a $60 CPU that wouldn’t make the 50% overclock to 550MHz. 

The 366’s success was followed up by the Celeron 400 at 600MHz craze which is still going on; unfortunately, Celerons that boast a clock speed higher than 400 often have more difficulty achieving the same overclocking success as their predecessors because of their high clock multipliers.

Since all of the Celeron CPUs are clock locked (their clock multiplier cannot be adjusted), anything above the 6.0x clock multiplier of the Celeron 400 is virtually useless with the 100MHz FSB.  The next step up, 6.5 x 100MHz would result in a 650MHz overclock for the Celeron 433 which is just over the top of the theoretical maximum of Intel’s current 0.25-micron process.  So owners of Celerons with clock multipliers greater than 6.0x have to resort to FSB settings less than 100MHz to reach that 600MHz mark. 

Luckily, the way the math works out, the 8.0x clock multiplier on the Celeron 533 works beautifully with the 75MHz FSB (a very common and very reasonable FSB setting) to produce a 600MHz overclock.  Using the 83MHz FSB setting, another very common and reasonable FSB setting, pushes the 533 up to around 667MHz which, unfortunately, is not very reasonable for the 0.25-micron CPU.  If you’re lucky enough to have a motherboard with 1MHz FSB increments from 66MHz up to 100MHz then you may be able to get a little more out of the Celeron 533, but for the most part, 600MHz is about as far as you’ll be able to push this puppy with conventional cooling methods.