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Duron 950 to Athlon XP 1.7+ in the test: AMD processor Roundup

Duron 950 to Athlon XP 1.7+ in the test: AMD processor Roundup

Overclocking

An important factor for the success of the Athlon and of course the Duron processor in the end user market was and is certainly the overclocking potential of the CPUs. The fact that the Athlon with Thunderbird and the old Duron with Spitfire core can use a simple trick to vary the clock multiplier on suitable motherboards has had a positive impact on the campaign of these processors. An Athlon Thunderbird runs at 1.4 GHz with a bit of luck and appropriate cooling with 1.53 or even 1.6 GHz, without the other system components such as AGP graphics card, PCI plug-in cards or the main memory through an excessive front-side bus - or AGP or PCI clockto get out of step. Since the competition, above all Intel, have been delivering their own processors with a fixed multiplier since the first Pentium MMX, overclocking is only possible by increasing the system clock (FSB), which means that all other system components have to be operated outside of their specifications This can lead to complications earlier.

While the multiplier lock on the new Duron is very easy with the pencil trick by connecting the L1 -Bridges can be lifted, you are faced with a medium-sized problem with the Athlon XP. The resistance of the pencil graphite is simply too great, so that the signal flow is no longer given. Furthermore, during the production of the Athlon XP, when AMD cuts through the L1 bridges to determine the final multiplier, a small hole is burned in the processor package. In contrast to the ceramic case in which the old desktop and server Athlons and all Duron processors are packed, the organic case of the Athlon XP is significantly softer. This small hole makes direct connection almost impossible. Since necessity is known to make people inventive, there are now numerous instructions on the web that also explain how to “unlock” the Athlon XP. In most cases, highly conductive silver lacquer is used, with either 'painting' around the holes to the side or, if necessary, the holes first filled with a non-conductive material, such as glue, and then the L1 bridges with silver lacquer on top Paths to be connected. Both ways lead to the desired goal.

Unlock Athlon XP
Athlon XPMultiplier pins

However, there is nowhere near as much potential in the new Athlon XP processors as there is in the Athlons with a Thunderbird core has been. In addition to the waste heat, you quickly reach the limits of the multipliers. These are passed to the processor via four pins on the bottom of the CPU (FID [3], FID [2], FID [1] and FID [0]). Transferring is actually the wrong expression, because it is actually about output signals (2.5V) that tell the chipset which SIP (Serialization Initialization Packet) should be sent to the processor. As soon as the multiplier lock of the processor has been overcome, the BIOS has the say and reports the corresponding SIP to the chipset. The processor now accepts any multiplier when starting. However, since the multiplier is only set via four pins and thus has a data width of only 4 bits, the number of possible combinations is limited to a total of 16. The following list shows the 4-bit coding of the pins for the multiplier.

FID [3: 0] Multiplier pin coding
FID [3] FID [0] FID [1] FID [0] Multiplier 0 0 0 0 11 0 0 0 1 11.5 0 0 1 0 12 0 0 1 1> = 12.5 0 1 0 0 5 0 1 0 1 5.5 0 1 1 0 6 0 1 1 1 6.5 1 0 0 0 7 1 0 0 1 7.5 1 0 1 0 8 1 0 1 1 8.5 1 1 0 0 9 1 1 0 1 9.5 1 1 1 0 10 1 1 1 1 10.5

As we can see, all multipliers above 12.5 received the same coding. No multiplier above 12.5 can therefore be set in the BIOS, all multipliers above thisThe value must therefore be regulated in the processor itself. For example, if you have an Athlon XP 1.9+, which runs with a real clock rate of 1.6GHz and whose multiplier is already 12.0, you can only use this processor with 12.0 without changing the front-side bus. 5 x 133MHz, i.e. 1.66GHz, overclock. The Athlon XP 2.0+ will offer exactly this rate, overclocking this processor via the multiplier is no longer possible.

On the next page: Known errors