Celeron overclocking.

See also, C-566 overclocking.

I recently wanted to get a new computer (what else is new?), and decided now was the time. I figure the best time to upgrade is when the latest technology about doubles. With the P2-450's out, my P-200 was looking pretty old. I looked into pricing on the new chips. Guess what? THEY'RE EXPENSIVE! We're talking $650.00 for a P2-450. I trashed that idea, but I had heard some rumors about "overclocking," which is taking your normal Pentium or Pentium II CPU and adjusting the timing on your motherboard, thereby making the CPU work faster than it was designed to. It's relatively easy to make a Pentium 200 work at a speed of 266mhz (roughly 25% increase in performance). Generally it's a lot of trouble to go through for a small boost in speed, but to hardcore tech geek it's the equivalent of getting a few more horsepower from your muscle car. It's all about bragging rights.

What recently set the Internet community abuzz was the introduction of the Pentium II "Celeron" chip. It's your basic Pentium II aimed at the low-end market to compete with AMD and Cyrix, two rival chip makers. The really cool thing about this chip is that it lends itself to massive overclocking, in the neighborhood of 80%. There were lots rumors about getting the Celeron 300 chip to run at 500+ mhz, a pretty sizable increase. The best thing about this Celeron chip is the price - about $100.00. I started doing some research - is it really possible to pay $100.00 for a chip that will outperform a $650.00 chip? What I found was pretty interesting.

The Celeron is easy to overclock for two reasons:

1. No slot-1 case. The new Pentium-2 chips come encased in a plastic cartridge, unlike the previous chips that plugged directly into the motherboard via the pins. The cartridge may make the chip safer but they make the chip difficult to cool. The key to overclocking is heat reduction. Since the Celeron chip has no plastic case it's possible to attach a heatsink directly to the chip. Add some fans to the heatsink (I have three), and you're able to cool the chip much more easily than when it's in a cartridge.

Celeron chip - no case P2 chip - in case

2. CPU-speed L2 cache. The chip stores frequently accessed data in the L2 cache, thereby eliminating the need to access system memory for tasks that are commonly performed. It has an onboard cache of 128k rather than 256 on the P2. The first Celeron chips had no L2 cache at all, and performed "poorly" in the standard Windows applications, where common tasks are repeated over and over and over. By "poorly" I mean in the benchmarks, not necessarily real-world performance. At any rate, this L2 chache is not limited to the bus speed of the processor, but can go as fast as the chip itself. "Huh?" you're asking? Simply put, the memory cache is smaller but much faster. The speed of the cache is not limited to the speed of the CPU as is the case with the Pentium 2. You can therefore crank the speed of the chip and the cache memory will speed up too, which means the only thing limiting your overclocking speed is too much heat.

There were indeed lots of people reporting success with overclocking this chip. With the correct hardware it was almost guaranteed. So, I was hooked. I got the materials and my handy checklist and went to work. Lo and behold - it worked! I now have a fancy 450mhz machine at the low-low cost of about $500 in various parts - less than the cost of the P2-450 alone. The benchmarks for the top-end games are virtually identical to those of a standard P2-450. In business applications there is a benchmark difference, but in real-world computing the difference is not noticable.

Here's what you need:
Celeron 300a chip - Important! Don't get the 333a or the 300 (no "a"). The 300's have no cache at all and are not nearly as good. The 333a is clock-locked at a different level than the 300a, so you'd have to boost the 333a to 500+ mhz rather than 450, and the success rate at that speed is much lower.

Voltage regulating motherboard. You may need to adjust the voltage of your CPU to boost the speed - I did. The ABIT BH6 or BX6 do just that via the BIOS. They run about $100.00 and are very nice boards. "What's a BIOS?" you ask. Read the guides in the links below if you want more info.

Quality PC-100 RAM. PC-100 is the fastest RAM currently available. PC-100 means the RAM talks to the CPU at 100mhz. Most older RAM talks at 66mhz. The timing is essential if you're going to overclock.

Lots of fans and a good case. I had to get a new case to fit the the ATX motherboard. I added fans to the CPU heatsink (3) and a front fan to the case for good ventilation.

Time and patience. There's some troubleshooting you need to do, but if you're patient you should be able to get this setup to work great. You may have some crashes until you get all of your settings just right.

Send me email if you have questions There is tons of information on the subject, but these sites were very helpful:

http://www.anandtech.com - great component reviews.
http://www.sysdoc.pair.com - Tom's hardware guide - essential tech site.
http://www.sharkyextreme.com - complete overclocking guide.

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