What is the difference between AMD A64 and AMD A64"Winchester" ???
Newcastle (130nm) and Winchester (90nm) are codenames for CPUs manufactured using different processes, same basic architecture but the transistors and traces were "shrinked" so AMD could fit more cores onto the same waffer to increase their manufacturing capacity, decrease the heat output and ramp up the clockspeed.
Take the K7 architecture for example, the original Athlon was manufactured using a 250nm process with 512<font color=red>K</font color=red>B of off-die L2 cache (Slot A) and maxed out at 700MHz, AMD switched to a 180nm process for the K75 which maxed out at 1GHz.
Then came the Thunderbird for Socket A with 256KB of on-die cache, also manufactured on 180nm technology, it reached up to 1400MHz but ran extremely hot for its time.
The first Athlon XP was based on the Palomino core and was the last 180nm CPU, it featured most of Intel's SSE instructions and the 2100+ ran at 1733MHz. It was replaced by the short lived and rather lame Thoroughbred-A. Something went wrong with the shrink from 180nm to 130nm and that first Thoroughbred just would'nt run any faster than 2GHz, that core was a big deception among the AMD overclocking community.
AMD took a few months to fix their 130nm process and relased the Thoroughbred-B, the 2800+ ramped up all the way to 2250MHz. Unlike the A's, B's were able to reach much higher frequencies than what they were designed for, a 1.4GHz 1600+ could be overclocked to 2.3GHz with high end cooling and 2.0V !
AMD tweaked the Thoroughbred core again and introduced the Barton core with 512KB of L2 cache, it is not uncommon to see 1.8GHz 2500+ running at 2.5GHz with good cooling and a moderate voltage bump.
It seems like the K8 architecture will follow a similar path, the 90nm Winchester is AMD's most recent core and its overclocking potential is well known, 2.6GHz on stock cooling and voltage is nothing to sneeze at.
If you want to learn more, <A HREF="http://users.erols.com/chare/786.htm" target="_new">This</A> is a good place to start.
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