Mobile CPU’s Explained: It’s Not All About The Cores

“What’s the processor — Dual-core or Quad-core?”

“Is it 1.2GHz or 1.4GHz”

If I happened to overhear these questions five years ago, I’d be sure that the conversation was about computers. But now that smartphones have practically become pocketable computers, many people wanting to buy one are concerned about these technical specifications. Previously, big words like ‘multi-core’ were only boasted by flagship smartphones costing upwards of Rs. 30,000. But today, these ‘keywords’ are used to lure people into buying inexpensive phones that also boast of such ‘high-end’ features. What gives? How can a phone costing Rs. 15,000 have almost-matching specs as phones costing nearly twice as much? Something has got to give.

More Cores Does Not Always Equate to Faster Performance

We will take the example of two Samsung handsets to illustrate this — the Galaxy Grand Duos has a dual-core 1.2 GHz processor, while the newly launched Galaxy Grand Quattro has a 1.2 GHz quad-core chip. You might find it baffling that the latter model with the quad-core chip actually sells a couple of thousand rupees cheaper than the former with a dual-core CPU.

The trick here is that mobile chip makers have come up with quad-core processors targeted for cheap smartphones. Reading the fine-print will reveal that these quad-core CPUs are based on older architectures.

Whenever you’re reading about CPUs in a smartphone, you may come across the following terminologies — ‘ARM’, ‘Cortex’, ‘A5’ or ‘A7’ or ‘A9’. ARM is the name of a company that licences their architectures (branded Cortex) with different models coming up each year like the A series mentioned before.

Now, based on these architectures, chip makers like Qualcomm make the “Snapdragon” series of chipsets, or Samsung makes their own “Exynos” that powers their flagship handsets like the Note II (Cortex A9) or the Galaxy S4 (Cortex A15). NVIDIA uses the same ARM architecture to produce their Tegra range of chipsets. The MediaTek chipset in the Micromax Canvas HD A116 is based on the ARM Cortex A7.

So, the quad-core chip in the Galaxy Grand Quattro is based on the ARM Cortex A5, while the Galaxy Grand Duos runs a dual-core Cortex A9 based one. Also, remember that real performance would also depend upon how well the OS is optimised to make good use of all the cores of the CPU. Probably one of the reasons why we didn’t find the Quattro to run any smoother than the Galaxy Grand in our usage, despite benchmarks suggesting that the former is faster than the latter. So “quad-core” merely serves as a glorious sticker on the box to help sell the handset better in a cut-throat competitive market.

Don’t Forget to check out the Graphics Chip

Though benchmarks may suggest that a quad-core chip is better than the dual-core, it’s not just up to the CPU to determine the overall performance. Because the Quattro is fitted with a less powerful Adreno 203 graphics chip, seemingly because of which, video recording on the phone is capped to just 720 x 480 pixels (that’s DVD resolution). Whereas, the Galaxy Grand’s Broadcom VideoCore IV GPU is capable of recording and playing back video in 1080p Full HD. The lower-end graphics chip will also serve as a bottleneck in graphics-intensive games.

Bottom line — It’s not just all about the cores.

It’s worth knowing what kind of chipset does the mobile device use. Lastly, true performance simply cannot be judged by looking at these numbers, while actually using the phone will reveal the how smooth the interface really is or how well can the device multitask with many apps open.