Sort of defeats the purpose of the Celeron, right? Not exactly. If you recall, the Celeron was originally designed to be a low cost alternative to the Pentium II directly from Intel, eliminating the need for a buyer to consider purchasing a non-Intel processor to get a good value. By adding on a mere 128KB of L2 cache, and by placing it on the processor's die itself, you increase the production costs of the Celeron A over the Celeron by an insignificant percentage while boosting overall performance by an enormous amount.
The 128KB of L2 cache is enough to boost the performance of a Celeron A to Pentium II levels of performance in most standardized tasks, while servers will want to stick to the Pentium II as a processing platform due to its larger 512KB cache, the Celeron 300A is more than enough for your standard desktop system up to a high end gaming system. How can a 300MHz Celeron be turned into a high end gaming system? Very easily actually, however let's take a look at the properties of the Celeron 300A before jumping into that pool.
Smarter than the Average Bear
The Celeron 300A will work on any LX, BX, or EX based Slot-1 motherboard that does have support for a Pentium II with 128KB of L2 cache. Now the only motherboard that shipped directly from the manufacturer with this support stated clearly in the manual was the ASUS P2B, not even the ABIT BX6 has support for the 300A out of the box. Provided you get the latest revision of a motherboard with the newest flash BIOS installed, you shouldn't have any problems, however you will definitely want to give you motherboard manufacturer's homepage a quick visit before upgrading to a Celeron 300A (or a 333) for any BIOS updates. The test bed for AnandTech's Celeron 300A system was an ABIT BH6 which, although booted up fine with the 300A installed, was flashed to include the latest BIOS with Celeron 300A/333 support.
Now keep in mind that both the Celeron 300A and the Celeron 333 are 66MHz FSB processors, meaning they were designed for use with the 66MHz Front Side Bus frequency and on those motherboards that auto-detect the FSB setting these processors will report as being 66MHz parts. The 300A runs at 66 x 4.5, and the 333 runs at a clean 66 x 5.0.
Intel, being smarter than the average bear, took certain precautions to make sure that the Celeron 300A would run at 300MHz and the Celeron 333 would run at 333MHz. Unlike older Intel and non-Intel processors, the Celeron is a clock-locked processor meaning that it recognizes a single clock multiplier. Why didn't Intel implement a frequency lock? Since the entire purpose of clock-locking a processor is to prevent the remarking of chips, clock locking allows for a Celeron 300A, for example, to be sold only as a 300A since it cannot be clocked any differently using a higher clock multiplier. Frequency locking the chip would only increase production costs and achieve virtually the same effect as far as combating remarking goes. Looking at the big picture, Intel isn't really affected by overclocking on a large scale, it is the large scale remarking of processors that hurts them the most, which is what they are trying to fight by clock locking their processors.
So, what we have is a Slot-1 processor, which will work in any LX/BX/EX Slot-1 Pentium II motherboard (with the proper BIOS updates), that operates at the 66MHz FSB frequency and is clock locked at a fixed multiplier, in this case, 4.5x...but how can you possibly crank out the power high end gamers desire from their system out of a cheap alternative?