Revealed: Unlocking AMD's Overclocking Protection
This task is a challenge especially for users who are fond of overclocking. What has happened so far? AMD locks its new TBird Athlons and Duron processors in SocketA packaging (CPGA) with a fixed multiplier to prevent CPU operation beyond the defined specification. The manufacturer uses the same method as competitor Intel for the Celeron and Pentium processors. However, in practice there are significant differences: While Intel equips its CPUs with special SRAM registers (multiplier lock) to prevent tampering with the multiplier, AMD supplies all its processors with small integrated contact bridges (L1 to L7) on the topside of the case. The actual coding of multiplier and core voltage is done with a CO2 laser by cutting the contacts depending on the processor type.
In the article , we already discovered the combinations for the contact bridges. But we had a CPU without multiplier lock for this test and thus were able to overclock the Duron 700 on the Asus A7V without any problems. Back then the Asus A7V was an exception among the available boards with SocketA (a.k.a. Socket462) and VIA KT133 chipset: An additional DIP switch on the board allowed changing the multiplier. This enabled us to easily overclock CPUs without fixed multiplier. Today the situation is slightly different though: AMD does not ship processors without a fixed multiplier anymore, and the revised Asus A7V has no DIP switch for the multiplier.
For this reason we developed modification instructions that enable circumventing the fixed multiplier of any new Duron or Thunderbird processor on an Asus A7V. The great thing about this handy work: The necessary components only cost about 3 US Dollars, and the expected performance increase is about 30 to 35 percent! For example: Our Duron 700 runs completely stable at 900 MHz!
