Same Size, but Twice the Cores
Obviously the biggest improvement Yonah offers over Dothan is the fact that it’s dual core. But where things get interesting is that thanks to Yonah’s 65nm process, a dual core Yonah die is about the same size as a single core Dothan die - in other words, it costs Intel just as much to make a dual core Yonah, as it did for them to make a single core Dothan.
A major reason the die size didn’t really go up much is because although Yonah has two cores, its L2 cache size remains unchanged at 2MB. Unlike the Pentium D, Yonah’s 2MB L2 cache is not split into two discrete 1MB caches, it is actually one whole 2MB cache that is shared by both cores. This is a very important distinction, as it means that Yonah is far from just two Dothans stuck together.
Source 10 Pages ReviewWhile the Yonah and Athlon 64 X2 systems consumed relatively similar power at idle, Yonah hardly eats up any more power under full load. In fact, a 2.0GHz Yonah under 100% load consumes less power than an Athlon 64 X2 3800+ at idle. Obviously Intel has the advantage of being on a much lower power 65nm process, but it won't be until the second half of next year before we see any Athlon 64 X2s at 65nm, so it is an advantage that Intel will have for quite some time.
As a desktop contender, Yonah is a bit of a mixed bag. While its performance in content creation applications has definitely improved over the single core Dothan, it still falls behind the Athlon 64 X2 in a handful of areas. Intel still needs to improve their video encoding and gaming performance, but it looks like we may have to wait for Conroe and Merom for that.