As the smartphone market has exploded over the past few years, an arms race between the companies that design the processors powering the devices has ensued. Qualcomm (QCOM 0.95%) has emerged the undisputed leader in the space, with other companies like NVIDIA (NVDA -0.32%) and MediaTek fighting for market share. Some device manufactures are even designing their own chips, like Samsung (NASDAQOTH: SSNLF) does for its Galaxy line of smartphones.
One way that these companies have been pushing performance higher has been by adding more cores. While the first smartphones were powered by single-core processors, the market has followed in the footsteps of the PC processor market by giving way to dual-core, and eventually quad-core, processors. But with some companies now selling octacore processors -- Samsung has an octacore version of its Galaxy S5 and MediaTek is pushing its octacore processors as an alternative to Qualcomm's high-end products -- it's important to understand that a greater number of cores does not necessarily lead to greater performance. In fact, more cores may end up being detrimental to the user experience, making only the spec sheet look more attractive.
The case against more cores
Having more cores in a processor means that a piece of software, whether it's running on a PC or a phone, can do more work concurrently. One example of a PC program that takes advantage of multiple cores is Microsoft's Excel. Excel can use all of the cores available in a PC in order to speed up complicated calculations, splitting up the work and providing a better user experience. Another example is Adobe Photoshop, where complicated image-processing calculations are done on millions of pixels.
But this ability has to be built into the software, and most programs don't take advantage of multiple cores. This means that the performance of this software depends mostly on the speed of a single core, and the number of cores has little effect. In most cases, it's better to have a fewer number of faster cores instead of a larger number of slower cores, as the user experience starts to suffer when the cores get too slow.
There's a reason why PC processors typically don't have more than four cores today: Most simply can't take advantage of a greater number than four.
With smartphone processors, an even stronger case against more cores can be made. Since multitasking on a smartphone is far more limited than on a PC, a greater number of cores offers little benefit for that purpose. Most smartphone users do only one task at a time, meaning that the performance of a single core is far more important than the number of cores. Smartphones also have a limited amount of power that can be used to run the processor, given that battery life suffers if more power is used, so doubling the number of cores necessitates making each core less powerful. In most cases, this leads to worse performance.
Why are octacore processors being pushed?
MediaTek was one of the first companies to announce an octacore processor, and the first devices using this chip are starting to be announced. MediaTek's goal is to take on Qualcomm at the high end, banking on consumers equating more cores with greater performance. Qualcomm, which derided octacore processors as "dumb" last year, has now announced an octacore processor of its own. The reason? Because that's what Chinese consumers want. A quote from a Qualcomm executive makes this clear:
Consumers in China want octa-core. It's very high on their list; while in the US and Western Europe, it's totally other things that consumers want. So we've really recognized that if that's what Chinese consumers want, that is what our Chinese customers, our OEMs want, and Qualcomm has to care for that need; so that's what we're doing.
Octacore smartphones are being built because of an irrational demand for more cores from Chinese consumers, not because they actually make the user experience better. MediaTek is basing its entire strategy on a gimmick, and Qualcomm is following suit.
Why NVIDIA has the right idea
NVIDIA, which as struggled to gain market share with its Tegra line of mobile processors, is going in the opposite direction. Its upcoming Tegra K1 processor, set to launch sometime this year, will come in two versions. The first version uses the same quad-core design that has become the standard in high-end phones and tablets, but the second version only sports two custom cores designed by NVIDIA.
These custom cores will be much more powerful than the cores powering the first version, and recent unofficial benchmarks have put the performance of both versions at roughly the same level. Two of NVIDIA's custom cores provide the same performance of four standard cores, and applications that run on only a single core should perform far better on the dual-core version.
Qualcomm remains the market leader, but its push into octacore processors is a dubious strategy meant to protect market share in China. This is a distraction, and it may allow companies like NVIDIA that focus on increasing performance for real use cases to pick up market share in the long run.
The bottom line
Octacore smartphones are a gimmick. MediaTek, in an attempt to differentiate itself from Qualcomm, is moving in the wrong direction, and Qualcomm is forced to follow in order to protect its market share in China. This creates an opportunity for more pragmatic companies to gain market share, as what ultimately matters is the user experience, not the spec sheet. If NVIDIA can stay out of the core war and instead focus on what really matters, the Tegra K1 has a real chance at success.