Dual-core technical data of Intel and AMD
The so-called dual-core processor is simply to integrate two processor cores on a CPU substrate and connect the processor cores through a parallel bus. Dual-core is not a new concept, but the most basic, simplest and easiest CMP (Chip Multiprocessor) type. In fact, in the field of RISC processors, dual-core or even multi-core has already been realized. CMP was first proposed by Stanford University in the United States. The idea is to implement SMP (Symmetric Multiprocessing) architecture in one chip and execute different processes in parallel. As early as the end of last century, Hewlett-Packard and IBM had put forward the feasibility design of dual-core processors. In 200 1 year, IBM introduced the POWER4 processor based on dual-core, and then Sun and Hewlett-Packard successively introduced the UltraSPARC and PA-RISC chips based on dual-core architecture. But at this time, the dual-core processor architecture is still in the high-end RISC field, and not long ago, Intel and AMD successively launched their own dual-core processors, and dual-core really entered the mainstream X86 field.
The most important reason why Intel and AMD introduced dual-core processors is that the main frequency of the original ordinary single-core processors is difficult to improve and the performance has not made a qualitative leap. Because the frequency is difficult to improve, Intel had to announce plans to stop 4GHz products after releasing 3.8GHz products. However, AMD can't greatly improve after the actual frequency exceeds 2GHz, and 3GHz has become an insurmountable hurdle for AMD. It is in this case that in order to find new selling points, both Intel and AMD have raised the banner of dual-core.
Introduction of Intel Dual-Core Processor
Intel's current desktop dual-core processor is code-named Smithfield, which can basically be considered as integrating two Prescott cores adopted by Pentium 4 into the same processor. The two cores * * * share the front-end bus, and each core has an independent secondary cache of 1MB, which adds up to 2MB * *, but this is obviously different from the 2MB cache of Pentium 4 6XX series processors. However, because the two cores in the processor have independent caches, it is necessary to ensure that the cache information of each physical core must be consistent, otherwise there will be operational errors. For example, a = 1 is recorded in the memory data area of the system; If the first processor core reads and writes this data area and rewrites it to A = 0, then the cache of the second processor core must also be updated to A = 0, otherwise the data will be wrong in future operations. This process is the consistency of cache data, which means that dual-core processors need "arbiters" to coordinate. In order to solve this problem, Intel handed this coordination work to the North Bridge Chip (MCH or GMCH): when two cores need to update the data cached in the processor synchronously, they need to update it through the front-end bus and then through the North Bridge. Although the cached data is not huge, it will undoubtedly bring some delay because it needs to be processed through the north bridge, and the communication between cores will become slow, which will greatly affect the performance of the processor.
Intel's current desktop dual-core processor products are divided into two series: Pentium D and Pentium EE. Among them, Pentium D includes 820(2.8GHz), 830(3.0GHz) and 840(3.2GHz), which adopts 800MHz FSB and faces the mainstream market. At present, Pentium EE has only one 840(3.2GHz), which also uses 800MHz FSB for high-end applications. Pentium d and Pentium EE both adopt 0.09 micron process and LGA775 interface; The main difference between them is that Pentium EE supports Hyper-Threading Technology, while Pentium D does not support Hyper-Threading Technology, which means that when Hyper-Threading Technology is turned on, Pentium EE will be recognized as four processors by the operating system.
As for motherboard chipset, Northbridge chip plays an important role in cache data processing and exchange among different cores. At present, 945/955 series can support Pentium D and Pentium EE, but 9 15/925 can't. Even if you can boot on the 9 15/925 motherboard, you can only use one dual core!
Brief introduction of AMD dual-core processor
AMD's current desktop dual-core processors are code-named Toledo and Manchester. Basically, it can be simply regarded as integrating the two Venice cores adopted by Athlon 64 into the same processor. Each core has an independent L2 cache of 5 12KB or 1MB, and the two cores * * * enjoy Hyper Transport, which is basically the same as the current Athlon 64 architecture. However, unlike Intel's dual-core processor, AMD's Athlon 64 processor integrates a memory controller. Athlon 64 is designed for dual-core, but it still needs an arbiter to ensure the consistency of its cached data. AMD adopted SRQ (System Request Queue) technology here. At work, each core puts its request in SRQ, and when resources are obtained, the request will be sent to the corresponding execution core, so the consistency of its cached data can be completed directly in the processor without going through the Northbridge chip. Compared with Intel's dual-core processor, its advantage is that the delay of caching data is greatly reduced.
AMD's current desktop dual-core processor is Athlon 64 X2, and the models are divided into 3800+ to 4800+ according to the PR value. It also adopts 0.09 micron technology, Socket 939 interface, supports Hyper Transport at 65,438+0 GHz, and of course supports dual-channel DDR memory technology.
Because the arbiter of AMD dual-core processor is CPU instead of Northbridge chip, the choice of motherboard chipset is much looser than Intel dual-core processor, and it can even be said that it has nothing to do with motherboard chipset. Theoretically, any motherboard of Socket 939 can support Athlon 64 X2 by updating BIOS. For ordinary consumers, this can protect the existing investment, and there is no need to upgrade the motherboard at the same time as the Intel dual-core processor.
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