The history of computing is full of interesting anecdotes, and the AMD K7 Athlon Thunderbird processor series earned itself, on its own merits, a privileged place in said history. As we are reminded from TechSpot, this generation underwent laser trimming to separate the L1 cache bridges, making it impossible for users to change the multiplier clock. The AMD K7s were also one of the most important generations in the history of AMD.
As our more advanced readers will have already guessed, this implied that the AMD K7 Athlon Thunderbird series came with the multiplier locked, and therefore it was not possible to overclock them, but why did AMD do this? We find the answer in the picaresque of the shops of the time, that took advantage of the unlocked multiplier processors to raise them in frequency, and market them as if they were superior models, charging a much higher price for them.
A priori, that laser cutting seemed a totally effective, and insurmountable, way to put an end to such practices, but human ingenuity soon made an appearance, and it was soon discovered that it was possible reconnect the L1 cache bridges using a material that is minimally conductive. Yes, a conductive material was enough to join both bridges, and a simple pencil ended up becoming an economical solution, but very effective, since graphite is a conductive material.
The ceramic package of the AMD K7 Athlon Thunderbird was also very important
This is another essential piece of information to understand how it was possible to use a graphite pencil to connect the bridges of the L1 cache. As some of our readers will recall, processors have not always used the current design based on a PC and a metal IHS. The AMD K7 Athlon Thunderbird, and many other earlier models, used a ceramic encapsulation, which made it very easy to create a bridge to connect the L1 cache, as can be seen in the attached image.
It wasn’t complicated, but the truth is that it was quite scary to carry out this process, including despite the ceramic encapsulation of the AMD K7 Athlon Thunderbird, since we had to ‘connect the bridges by rubbing the pencil back and forth over them about twenty times, until it was a dark black color, and not the normal gold color. ». We also had to make sure that the bridges are connected, but not touching each other.
Over time, this method was no longer viable, since AMD transitioned to PCB and IHS-based CPU design, which made that laser cutting could no longer be solved with a simple pencil. If you want more information on this topic, I invite you to take a look at this article, where you will find a guide on how to overclock an AMD Athlon XP processor based on PCB, and with said laser cutting.