Single-core
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A single-core processor is a microprocessor with a single core on a chip, running a single thread at any one time. The term became common after the emergence of multi-core processors (which have several independent processors on a single chip) to distinguish non-multi-core designs. For example, intel released a "core 2 solo" and "core 2 duo", and one would refer to the former as the 'single-core' variant. Most microprocessors prior to the multi-core era are single-core. The class of many-core processors follows on from multi-core, in a progression showing increasing parallelism over time.
Processors remained single-core until it was impossible to achieve performance gains from the increased clock speed and transistor count allowed by Moore's law (there were diminishing returns to increasing the depth of a pipeline, increasing cache sizes , or adding execution units). [1]
Increasing parallel trend
- single-core - one processor on a die.
- multi-core - a 'few' processors on a die,e.g. 2,4,8. As of 2016, most CPUs fall into this category.
- many-core - a 'large number' of processors on a die, e.g. 10s, 100s, 1000's. Some specialist ASICs/Accelerators and GPUs fall into this category.