Core i7 vs. Core 2 Quad: Fair Comparison

 It is evident that SMT and Turbo Boost Technology are enough for Core i7 processors to be faster than their quad-core predecessors from Core 2 family. That is why it is especially interesting to see the difference between the performance of the old and new generation processors without these new technologies.

So we compared the results obtained on Core i7-965 Extreme Edition processor from Nehalem generation against those of Core 2 Extreme QX9770 from Penryn generation. Both these CPUs work at 3.2 GHz frequency, therefore the obtained results show how much more progressive the new Nehalem microarchitecture is without SMT and Turbo Boost in the picture.

Overall, Core i7 processor is faster than the previous generation CPU even if it doesn’t have its main trumps – SMT and Turbo Boost Technology support. Frankly speaking, we didn’t expect any other result, because new Intel processors have a very strong memory controller and efficient cache-memory subsystem. It is a different thing that gives us some cause for concern. It turns out there are applications where “sterilized” Core i7 may fall behind the previous generation CPU working at the same clock speed. And it was especially surprising that among these applications there are a lot of games, which are very sensitive to the memory subsystem performance. It must be the differences in cache-memory organization of the new and old CPUs that affect the results like that.

L1 cache of the new processors is slower than that of the Core 2 CPUs, but faster L2 cache cannot make up for this drawback because of its very small size. Moreover, quad-core Core 2 processors can also boast large overall cache-memory capacity.

So, the obtained results let us conclude that Nehalem microarchitecture has no revolutionary innovations that could put these CPUs way ahead of their predecessors.