However, our practical tests showed a slightly different result. Before will actually tell you about our overclocking achievements, I would like to mention that we used different memory for overclocking. The Corsair CMX512-3200LLPRO memory, which we use for regular testing works perfectly well at the nominal frequency and with low memory timings. However, as soon as we increase the memory bus working frequency, the modules get significantly less stable. That is why I decided to use special overclocker’s memory for our overclocking experiments. It was OCZ PC4000 Dual Channel Gold Edition, which is guaranteed to work fine at the frequencies up to 500MHz. This memory allowed us to overclock Athlon 64 3000+ processor without increasing the memory frequency divider, which was set at 1/10 of the CPU frequency through the entire test session (DDR400, if we use the terms of BIOS Setup).

To ensure that we achieve better results during overclocking, we increased the processor Vcore by 10%, namely up to 1.65V, and then started increasing the FSB frequency very smoothly. The first problems turned up when we reached 222MHz FSB frequency. To be more exact, the RAID array simply refused to work properly. It turned out that the SerialATA RAID controller built into the VIA VT8237 South Bridge is very sensitive to the PCI bus frequency increase. When the FSB frequency reached 222MHz, the PCI frequency was only 37MHz, however, it was more than enough for the SerialATA RAID controller to lose its stability. That is why I carried out all ongoing overclocking experiments with a Parallel ATA hard disk drive – Western Digital Caviar WD400JB. Luckily, Parallel ATA controller of the VIA VT8237 South Bridge behaves much better during overclocking.

However, the change of the disk subsystem didn’t improve the situation that much. Having reached 226MHz FSB the system grew unstable again. This time it was the because of the CPU. To make sure that this not an accidental result, we went 1MHz back and ran the entire set of stability tests. We discovered no problems whatsoever, that is why I have every right to claim 2250MHz to be the maximum result our CPU managed to achieve during overclocking.

As you remember, the processor Vcore during overclocking was set to 1.65V, while the increase of the FSB frequency to 225MHz pushed the other system buses to 450MHz for the memory bus, 37.5MHz for the PCI bus, 75MHz for the AGP bus and 900MHz for HyperTransport bus.

I would hardly call this result a good one. We managed to speed up the CPU by only 12% above the nominal value. Moreover, we failed to reach the frequency our Athlon 64 3200+ achieved during overclocking, even though the two processors are based on the same core. It probably has to do with the fact that for Athlon 64 3000+ processors AMD uses defective dies, which cannot be used for more expensive Athlon 64 3200+ CPUs any more.

However, even a 10% frequency growth is a good result, which shouldn’t be neglected. Among the benchmark results later in this article you will also find the numbers indicating the performance of our system working with an AMD Athlon 64 3000+ processor overclocked to 2.2GHz by raising the FSB frequency to 220MHz. I considered it fair to test the system with 220MHz FSB because in this case all subsystems including SerialATA did work fine. The memory in this case worked at 440MHz and used 2.5-3-3-6 timings.