Een Spaanstalige vraag kwam binnen naar aanleiding van de recente lancering van de Intel Core i7 Extreme Edition. Hieronder alvast antwoord in Engels.
Original Question translated to English
"I’d like an expert to clarify following: What happen with the Intel core 2 extreme processor with 12 mega cache and a FSB of 1.333mhz. it’s because now I see that Intel ® Core ™ i7 Extreme Edition processor hardly has 8 mega de cache and a FSB of only 1066mhz. Is the Intel Core i7 Extreme more powerful? What is the difference in cores? What is the difference in terms of capacity? Why only 8 megas cache and lower bus now? Are we going back instead of going forward?
A short answer:
We're comparing two different processor architectures here: 'Penryn' for the QX9770, and 'Westmere' for the Core i7-980X. As a result of this it might give - on first sight - the impression to go a step backward. The reality on the other hand is a major step forward. The best way to compare processor performance is through the use of benchmarks, and plenty are out there these days showing the big performance differences.(eg. the review on hardware.info contains plenty of benchmarks comparing the new Intel Core i7 980X with others including the former extreme QX9770 - http://www.hardware.info/nl-NL/articles/amdnaWpvZGOa/Test_Intel_Core_i7_980X_Gulftown/4 ).
Let me give some more background on the above questions:
Explaining some key processor architecture differences, will help here.
a) Core difference: The QX9770 has 4 cores, while the new Core i7 980X has 6 cores. Next to the fact that the architecture of each new core is much more improved, you basically have 1,5 times more compute engines available in the 980X to complete your work. Both CPU's have multi-threading, so being able to handle 8 threads (QX9770) and 12 threads (i7-980X) simultaneously.
b) Frequency differences: The Core-i7 CPU's contain a feature called 'Turbo', this allow the CPU to increase his internal clock frequency when there's performance demand and the thermal specifications are met. As a result of this the base frequency can be a bit lower, but when needed it will go up. (in this case to 3.6Ghz). The QX9770 is standard 3.2Ghz, and can't speed up automatically. Why turbo is important - extra frequency power when needed - and it helps the "HUGI" idea ('hurry up and get idle') so saving power.
c) Cache difference: Due to architecture changes, we need to compare apples wiht apples here. The QX9770 has 3MB of Level 2 Cache per core => 12MB L2, where the Core-i7 980X contains 256KB of Level 2 cache per Core, but with a large shared 12MB of Level 3 Cache additionally. Because of the extra Level 3 cache in the i7-980X integrated and being shared over all cores, it works as an additional storage buffer, reducing the number of times the CPU needs to get data from 'slow' external memory. This combined with the smaller blocks of L2 cache gives a much more performing cache structure than in previous generation processors.
d) FSB / QPI / memory bandwidth: Front Side Bus was important in previous processor generations, because all I/O communication, including the memory access, had to go over this bus. The faster the bus, the higher bandwidth basically. With the Nehalem/Westmere architecture we integrated the memory controller into the processor, so no FSB exist in between anymore. This combined with the fact that there's now 3 memory channels gives a +/-2.5X higher memory bandwidth. Also PCI-E 2.0 interface is integrated in the processor architecture now. The remaining I/O communication goes over a new serial-type connection called QPI (Quick Path Interconnect).
PS. a very useful tool to compare Intel processor & product features can be found at: http://ark.intel.com/