In the initial stages of 1990's, clock speeds of the processor are considered as the real power of a chipset. However, that isn't the case anymore these days with chip makers upped their ante and released more core processors which are useful in one aspect and can't be useful in many ways.
Three years, there are dual-core processor smartphones which powered many smartphones at that point of time. Quickly, chip makers such as Qualcomm, MediaTek entered the segment and changed the entire scenario.
Many people believe that the usage of octa-core processors are quite a messy thing and can degrade some of their smartphone's abilities. Here are the myths of octa-core processors which are actually true.
Recently, Google ended support for Nexus 5 by not releasing Android N for it. However, developers from XDA Forums have already ported Android N custom ROM for Nexus 5. So, you can enjoy Android N features on Nexus 5 now. Cool isn't?
Most of the apps can't use all eight cores
It is to be noted that there are only some apps which use the full potential of octa-core processors. There are plethora of apps which are designed to run on any smartphone irrespective of the smartphone's chipset.
Battery life will be affected
More cores lead in exhausting of battery life in your smartphone. The architecture of the chipset is designed in a way that the smartphone uses the cores whenever it is required. That said, this will ultimately lead to ending up in battery life.
A Marketing Gimmick!
Many smartphones which arrived with octa-core processors will be divided into two quad-core chipsets. Manufacturers claim that one quad-core chip will be active all the time and the other one will be useful whenever it is required.
It will be helpful in PC's but not smartphones
Octa-Core chipsets are being used in many PC's and laptops and they can be customized to use all the cores at a time. Lately, many smartphone manufacturers started allowing users to tweak the chipset settings. You can't just purchase a smartphone for just playing an Asphalt 8 or Nova 3 game.
More cores don't result in longer software upgrades!
This is a hypothetical question. Just keep in mind that every smartphone company only provides support for 18 months including the official Android maintainer Google. Some smartphones will receive updates beyond their 18 months period.