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Maximizing the usage of the computing resources provided by multi-core processors requires adjustments both to the [[operating system]] (OS) support and to existing application software. Also, the ability of multi-core processors to increase application performance depends on the use of multiple threads within applications.
Integration of a multi-core chip can lower the chip production yields. They are also more difficult to manage thermally than lower-density single-core designs. Intel has partially countered this first problem by creating its quad-core designs by combining two dual-core ones on a single die with a unified cache, hence any two working dual-core dies can be used, as opposed to producing four cores on a single die and requiring all four to work to produce a quad-core CPU. From an architectural point of view, ultimately, single CPU designs may make better use of the silicon surface area than multiprocessing cores, so a development commitment to this architecture may carry the risk of obsolescence. Finally, raw processing power is not the only constraint on system performance. Two processing cores sharing the same system bus and memory bandwidth limits the real-world performance advantage. In a 2009 report, Dr Jun Ni showed that if a single core is close to being memory-bandwidth limited, then going to dual-core might give 30% to 70% improvement; if memory bandwidth is not a problem, then a 90% improvement can be expected; however, [[Amdahl's law]] makes this claim dubious.<ref name="Enabling Technology of Multi-core Processing for Medical Imaging">{{cite web|last=Ni|first=Jun|title=Enabling Technology of Multi-core Computing for Medical Imaging|url=http://www.uiowa.edu/mihpclab/presentations/staffPresentations/2009_12_22_Multi-core%20Programming%20for%20Medical%20Imaging.pdf|access-date=17 February 2013|archive-url=https://web.archive.org/web/20100705213827/http://www.uiowa.edu/mihpclab/presentations/staffPresentations/2009_12_22_Multi-core%20Programming%20for%20Medical%20Imaging.pdf|archive-date=2010-07-05|url-status=dead}}</ref> It would be possible for an application that used two CPUs to end up running faster on a single-core one if communication between the CPUs was the limiting factor, which would count as more than 100% improvement.
==Hardware==
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