AMD Athlon 64 3500+ Winchester Overclocking Experience

Although AMD is not yet using the new 90nm Winchester cores for the top Athlon 6 processor models, it doesn’t at all mean that the frequency potential of this core is lower than that of the 130nm NewCastle. Maybe the introduction of the new processor core in the low-end models of the family in the first place is justified by purely economical reasons described above. Therefore, when we managed to get hold of the Winchester based CPU we first of all decided to test its overclocking potential.

So, for our experiment we used Athlon 64 3500+ based on the 90nm core.

The diagnostic utilities launched when this CPU worked in the nominal mode provide the following report:

As we see, the nominal working frequency of this processor is 2.2GHz, and its default Vcore is 1.4V, which is 0.1V less than by Athlon 64 CPUs based on 130nm cores.

To test the overclockability of this CPU we assembled a test system including the following equipment:

• MSI K8N Neo2 Platinum mainboard (Socket 939, NVIDIA nForce3 250);
• 1024MB DDR500 SDRAM (Corsair CMX512-4000PRO, 2 x 512MB);
• Sapphire RADEON X800 XT graphics card (AGP 8x);
• Maxtor MaXLine III 250GB HDD (SATA150).

Since we didn’t aim at revealing the maximum frequencies one can get from this CPU with the help of extreme cooling solutions, we used a regular boxed cooler throughout our experiments. We overclocked the processor by changing the clock frequency generator settings, without changing the CPU clock frequency multiplier.

The testbed included DDR500 memory and a mainboard based on NVIDIA nForce3 250, which knows to lock the AGP/PCI frequencies when the clock generator frequency gets higher. Therefore, we didn’t have to worry about the factors limiting the overclocking results other than the potential of our processor.

First of all, we decided to check what maximum working frequency our Athlon 64 3500+ Winchester can achieve if the Vcore remains the same. Without much effort we managed to speed up the clock generator to 230MHz. keeping in mind that the nominal clock frequency multiplier of Athlon 64 3500+ processor equals 11x,, the overall CPU frequency grew up to 2.53GHz. Further system overclocking by continuous increase of the clock generator frequency resulted into unstable functioning of the system under workload that is why we had to increase the CPU Vcore, in order to be able to proceed.

The second part of our overclocking experiments was performed with the Vcore increased by 8.3%: up to 1.52V. This pretty insignificant voltage growth has had a great positive effect on the overclocking results, so that we could continue increasing the clock generator frequency without any stability losses. Step-by-step we managed to set a new stability limit: when the clock generator frequency reached 238MHz, the CPU remained stable, while any further frequency increase appeared impossible. This way, the maximum frequency we managed to achieve by overclocking AMD Athlon 64 3500+ on Winchester core appeared 2.618GHz.

In other words, we can state that the ultimate result is the practical ability of one of the first Athlon 64 processors on Winchester core to exceed the 2.6GHz bar with a minimal Vcore increase. Is that a lot or not? This is a good question. On the one hand, we didn’t get that greatly impressed with the frequency potential of the new 90nm Winchester core. Of course, regular Athlon 64 CPUs based on the 130nm CG core stepping cannot always exceed 2.6GHz, however, their maximum supported frequencies lie really close to this value. Moreover, Athlon 64 FX-55 processor manufactured with 130nm strained silicon technology already works at the nominal 2.6GHz. So, AMD can actually achieve the frequency of 2.6GHz without the 90nm process. On the other hand, despite the fact that the maximum working frequency of the today’s Winchester based Athlon 64 CPUs is only 2.2GHz, these processors are clearly capable of working at much higher speeds. Moreover, keep in mind that 90nm production technology hasn’t yet been fully mastered by AMD and is still under certain development and enhancement, so that we can expect the processor cores manufactured with this new technology to acquire a considerably higher frequency potential in the future. So, Winchester definitely does boast a huge potential, which will fully reveal itself later.

From this viewpoint Athlon 64 3000+ processor for Socket 939 appears a pretty good choice for an overclocker today. This CPU based on Winchester core after successful overclocking will be able to work at up to 2.6GHz frequency, which will make its performance competitive with that of top Athlon 64 models. At the same time, its price is now about $150. And the fact that it is designed for Socket 939 will allow overclockers to start assembling a very promising platform, which will be supported for a considerable while unlike Socket 754.