Is clock speed the be all and end all, and will mobile CPUs take over from PCs any time soon? We spoke to lead mobile strategist James Bruce about what really matters in a mobile CPU.
What really mattered when it came to mobile processors was a difficult question to answer, because it was also about what was important to the consumer; depending on how a phone was used, a lower performance processor would still deliver a good user experience, but for someone using the latest and greatest features of a phone, a higher performance processor would make sense, Bruce said.
“When you look at overall performance of handset, it is a combination, it’s the CPUSs, the number of CPUs, the graphics, the memory, the speed of the memory, all of those combine together to impact the user experience.”
Checking clock speed and RAM was a good way to start, but getting too obsessed with gigahertz was not the way to go; the difference between 1.5 and 1.7GHz was probably not going to make that much difference, but the difference between having 1GB of RAM and 2GB was a very big difference, Bruce said.
If someone were buying a phone which was subsidized by the operator and required a two year contract, it was best to buy the latest and greatest phone available. If the phone was being bought unsubsidized on Pay As You Go, life became more complex, Bruce said.
“In that situation you’ve really got to sit down as a consumer and think, what am I going to do with this phone? Am I just after a smart phone and to be honest I’m going to do a bit of social media, texting, some camera capture, a bit of video play back. If you’re that level there are a whole range of mid tier phones coming to market with quad core Cortex A7 which would do the job extremely well.”
Eight cores is fine
In What Mobile’s interview with Qualcomm, eight core processors (like Samsung’s new Exynos 5 Octa chip, which utilises ARM’s big LITTLE technology) were said to provide no better performance for more cost.
Bruce said the eight cores being differently sized – four big, four little – meant there was an improvement in performance; if there were eight cores of the same size, there would be no significant performance increase.
“What happens is that most of the time the four big cores are turned off and you’re running your typical phone load on the little cores and when you need the performance you just bring on the big cores as needed.”
The four little cores were incredibly capable for day to day tasks, Bruce said, and it was worth remembering that Qualcomm had announced they would be launching systems on chips using quad core cortex A7s, so was obviously happy with the performance of the ‘little’ cores for the markets they were targeting.
Switching between the little and big cores took no more time (“overhead) than what was happening on a typical phone, Bruce said.
In the future, four of the same core in any one mobile chipset was probably the maximum one could have, and using big LITTLE technology, eight was likely the maximum number of mixed cores on a smartphone, he said.
App developers are catching up
App developers always took a few months to take advantage of any massive increase in CPU capabilities in smartphones, but they were catching up fast, Bruce said.
“What’s happening is the app exosystem is very quickly taking advantage of the new features, the new capabilities fo these high end smartphones such that within six months they will be really using this increased power to deliver new applications.”
Developers also had to have the handsets in possession to develop apps for them, and this took time; we would probably begin to see optimised apps for the Galaxy S4 and HTC One in the next few months.
There was a trend happening this year for Android called GPU Compute, where tasks such as image processing were offloaded to the GPU, which was a very important part of the chipset. In the next year, we would see render script developing for Android, which allowed users to process video in real time and perform computational photography, enhancing the image processing video capabilities of a smartphone, Bruce said.
The advent of the mobile PC
Bruce said it was very likely mobile CPUs would replace PC CPUs; looking at the benchmark scores of the Samsung Octa or NVIDIA Tegra 4, they were almost at the performance point of a typical laptop.
We were on the cusp where systems on a chip were becoming incredibly capable and could be used not just in tablets but in laptop devices.
The fun zone – what phone do you use?
This morning a Galaxy S3, this afternoon an S4.
Fav app?
That’s a tough one, this might seem a bit boring, but probably the navigation ‘ I travel a lot and Google Maps is just so useful.
Fav film about computer chips?
When I’m watching movies, I try to get away from work.
Dream attachment to phone?
I would like my phone to be everything ‘ why do I need to carry keys, identity passes, all of that? It would be great for your phone to be everything, it would make my life so much easier because I’m very forgetful.
For What Mobile’s interview with Qualcomm’s vice president of marketing CDMA technologies, Tim McDonough, go here.
