Using multi-cores implies higher performance – is it the truth or myth? Well, in this blog, we will analyze the role of multi-core Processors in improving the performance. According to the GeekBench test results, Apple iPhone 6 with dual core A8 Processor has a higher performance rating for applications and memory activity compared to the octa-core Samsung Galaxy S6 Android Smartphone. A counter proof point shows an Android smartphone with octa-core performs faster than a quad-core variant. The performance of a chip depends on factors such as, number of cores, clock frequency, effective memory bandwidth, multi-thread efficiency, and cache coherency. These and other related factors govern the instruction per cycle which determines the application performance.
Clock speed is not the sole deciding factor on multi-core performance. Consider a dual core processor with base clock speeds of 3.5 GHz, and a quad core processor at 3.0GHz. For monolithic and single-threaded application, the dual core processor would outperform the quad core by 14%. Thus, if you have a single threaded program, dual core processor is recommended. In case of multi-threaded applications like video transposing, quad core processor would perform about 70% faster than dual core processors.
You can get the performance numbers at the GeekBench Web Site for the dual-core iPhone 6 (http://browser.primatelabs.com/geekbench3/4773885) and for the octa-core Samsung Galaxy S6 (http://browser.primatelabs.com/geekbench3/4028032). As is evident, the octa-core provides significant performance that is not replicated in the application performance. Single-Core instruction per watt of the dual-core is better than that of the octa-core.
Selection of the number of cores will be impacted by application capability, clock speed limits, power consumption, cache coherency algorithm, and operating system scheduling. Conducting early architecture exploration and system analysis on the proposed specification would give us an insight on the true performance. We will discuss about our recent simulation experiments in the upcoming blog.