Everything can be explained fairly simply. 130nm NewCastle core is 144sq.mm big. The die size of the new Winchester core shrank down to 84sq.mm due to the finer 90nm manufacturing technology. This way, the use of the 90nm process allowed AMD to design a 42% smaller processor core. All old NewCastle cores and new Winchester cores are currently manufactured in Dresden Fab30, which uses 200mm wafers. So, the new production technology allows obtaining 77% more cores per single wafer. In other words, the production cost of the Winchester core is ideally 44% lower than that of the least expensive 130nm core for the Athlon 64 processor family. However, this significant result can only be achieved if the yields per wafer are the same for 90nm and 130nm technologies. Of course, this is not yet the case. I really doubt that the new production technology can actually ensure the same high yields as the old 130nm process. In fact, AMD seems to be happy with the current yields for their new 90nm cores. The automated precision manufacturing methodology (APM) used on the Dresden Fab30 today allows polishing off the new technology within a very short period of time, so that already today the company can really benefit from selling the new slower CPU models manufactured with the 90nm process.

Since the current situation in the processor market doesn’t force AMD to increase the working frequencies of its processors that rapidly, AMD decided to start introducing 90nm Winchester cores into the slower processor models first, and then move over to the fastest ones. Especially, since there is a clear economical reason for this strategy. The first Winchester based processors are designed for Socket939 systems, support working frequencies from 1.8GHz to 2.2GHz and are rated as 3000+, 3200+ and 3500+. In other words, AMD managed to significantly enlarge the lower end of Athlon 64 processor family for Socket939 systems with the introduction of the new 90nm core. Now the least expensive CPUs from this product line cost around $150, which should make them much more popular.

Besides the reduction of production costs of the Athlon 64 processors, the launch of the 90nm technology allowed to improve their heat generation rate. While the 130nm NewCastle processors generated around 89W of heat, the 90nm Winchester solutions boast a much lower value of only 67W. This way, AMD managed to avoid leakage current issues, which caused Intel a lot of trouble during 90nm Prescott production: as you know the heat dissipation of Pentium 4 Prescott processors got notably lower than that of 130nm Pentium 4 Northwood CPUs.

This pretty impressive success of AMD Company, when the engineers managed to achieve a 25% heat dissipation drop by simply shifting to a finer 90nm production process has something to do with the nature of this technology. For the production of 90nm cores, just like to the production of 130nm cores, AMD uses SOI technology (silicon-on-insulator). As far as the strained silicon technology used for Intel’s 90nm processor is concerned, AMD refused to go with it yet. However the second-generation 90nm production process, which should be put into life next year, will include both: SOI and strained silicon. AMD engineers are very excited about this combined technology aka Strained Silicon Directly on Insulator (SSSDOI), since they expect it to open up new opportunities for further clock frequencies increase.

Moreover, in the upcoming E0 core stepping, which are due next year, AMD should introduce a few additional features. First of all, these processor dies will support SSE3 instructions, which have been implemented in Pentium 4 Prescott processors from the very beginning. Secondly, there will be 4 write combining buffers in the upcoming 90nm Athlon 64 cores instead of 2. And thirdly, AMD is planning to improve their power consumption. The today’s Athlon 64 based on Winchester D0 core stepping is similar to Athlon 64 on NewCastle CG core stepping.