Motherboards cannot always work with newer processors, even if those processors correspond to the standards of those motherboards. In such cases, the recommendation is to update the BIOS code. It often is difficult to implement this advice because it requires a second processor manufactured with the earlier technology. Unfortunately, few end users have a second processor at their disposal. In most cases, however, this compatibility problem can be solved by unlocking the frequency multiplier.
(Materials provided with the permission of http://www.overclockers.ru, a Russian-language Web site.)
Physically, AMD's first Athlon XP processors based on the Thoroughbred core (0.13-micrometer technology) were no different than Athlon XP processors based on the Palomino core (0.18-micrometer technology). The technological process changed, and the core area, operating voltage, and heat generation decreased. Nevertheless, the first models were practically identical in the internal structure of the die, the number of transistors, the amount of cache memory, and the FSB frequency.
AMD Athlon XP 2200+ based on the Thoroughbred core is a good example. Nominal frequency of this model is 1,800 MHz, the bus frequency is 133 MHz, and the multiplier 13.5x. Operating voltage of the processor is 1.65 V.
Despite the similarities between the Thoroughbred and Palomino architectures, unexpected difficulties were encountered when testing AMD Athlon XP 2200+ (AIRGA 0224WPAW) processors. Testing revealed that processors based on the Thoroughbred core are not supported by all motherboards. When processors based on the Palomino core were used, problems were not encountered with those motherboards. Furthermore, those motherboards were recommended on the AMD Web site for Athlon XP processors.
For all such cases, AMD recommends that you update the BIOS code. However, in most cases, it is impossible to accomplish this task. Problematic motherboards don't even start with processors based on the Thoroughbred core, and most users have no second processor compatible with the motherboard.
From several available motherboards, the Asus A7V333 revision 1.01 was chosen. It showed stable operation even with BIOS version 1005. AMD recommends using BIOS starting from version 1007.