As we are not 100% clear on what each individual bridge does in the L3 and L4 groupings, we simply focused on duplicating what we saw on the reference XP 1600+ chip. Their may in fact be other combinations which will work equally as well. After all the modifications had been completed the surface of the AthlonXP 2100+ looked like this:

After plugging in the newly modified AthlonXP 2100+ into our reference Epox 8KHA+ motherboard we were greeted with a very nice POST screen identifing it as an XP 1600+, which is exactly what we wanted to see.

Upon entering the BIOS on the Epox 8KHA+ we had full multiplier control from 6x-12.5x. Access to multiplier settings above 12.5x would no work however. Since we were not really interested in raising the multiplier above 12.5x this wasn't a concern. As you probably already know, lowering the multiplier and jacking up Front Side Bus results in higher overall system performance. Clock speed stayed around 1.9GHz (up from 1.73GHz of the native XP 2100+) with simple air cooling and a Vcore set to 1.85V.

Conclusions on theAXP21K+ Unlocking Trick

AMD has always said publicly that it wouldn't stop enthusiasts from getting the most from their processors, however the green AthlonXP 2100+ could not simply be unlocked with the standard "fill in the pits and connect the L1 bridges" technique. Has AMD implemented steps to make unlocking processors that much harder? Frankly we're not sure.

It was only after some time and considerable effort that we were able to piece together a plan of attack and come up with the AXP21K+ unlocking trick. While it most certainly put the life of the AthlonXP 2100+ processor in harms way, we were able to accomplish the task by slowly and carefully working on the tiny bridges on the surface of the OPGA.

Previous to the AXP21K+ unlocking trick we were able to overclock the AthlonXP 2100+ by simple FSB adjustments to 1.89GHz (145 FSB). After the AXP21K+ unlocking trick was engraved in OPGA (so to speak), we saw a clock speed of 1.9GHz with a FSB of around 180MHz. This means that while the processor clock speed is essentially the same as with the overclocked settings, there is a larger amount of bandwidth available to the processor which results in improved overall system performance.

If you have any questions, please post them in the forums so everyone can see them - I will not be replying to individual questions about this mod in email.

[Special thanks to Mike V. for being crazy enough to bring a Dremel to the surface of an AthlonXP 2100+! =)]