TI Conservative on Quad-core Chips for Mobile Devices
Concern about how well quad-core processors will work in mobile devices like smartphones and tablets means that Texas Instruments will focus on releasing chips with dual-core ARM processors for these applications, a company executive said this week.
Loading ARM-based quad-core chips may not be prudent for the current crop of handheld devices because of cost, thermal and heat limitations, said Avner Goren, general manager for OMAP strategy at Texas Instruments, in an interview.
TI's focus will remain on developing dual-core processors, which when combined with other cores such as video accelerators, will help mobile devices deliver a balanced performance while generating less heat, Goren said. Software has also not yet reached a point where it would work efficiently across four cores on mobile devices.
"You have to realize that at the end of the day you have to sell those devices and you have to be cost-competitive," Goren said.
Goren didn't rule out developing quad-core chips, but they need to fit in a device, meet the thermal budget, and take advantage of the software.
"Will it happen in the future? I cannot disclose. But it's not something I'm not looking into everyday. We are always trying to understand when is the next step, what is the right trade-off," Goren said.
TI's competitors such as Nvidia and Qualcomm are pushing for quad-core chips in mobile devices, saying the processors would boost application, web and graphics performance. Nvidia's upcoming Tegra 3 processor code-named Kal-El will be found on an upcoming tablet from Asus, which is due to be announced this month.
TI's OMAP application processors are used in tablets like Research in Motion's PlayBook tablet and Barnes and Nobles' Nook Color, and smartphones like Samsung's Galaxy SII and Motorola's Atrix 2. TI offers dual-core OMAP 4 processors based on the Cortex-A9 chip design, and will continue its dual-core march with successor OMAP 5, which is based on ARM's Cortex-A15 design and will be in production next year.
TI is taking a hybrid processor approach with OMAP 5. Two Cortex-A15 ARM processor cores run the main operating system and data intensive tasks, and companion Cortex-M4 processor cores run the real-time OS and perform secondary functions without disturbing the main processor cores. The chip design is similar to the OMAP 4470 chip, which has two CPUs for high-performance applications, and two low-power processor cores for secondary applications to prolong the battery life of devices.
OMAP 5 will be faster and more power efficient than OMAP 4, Goren said. The OMAP 5 will provide an average 60-percent power reduction compared to OMAP 4, more than double the processing performance and five-fold 3D graphics improvement. Virtualization capabilities on OMAP 5 chips could theoretically allow installations of Android and Microsoft's upcoming Windows 8 to work on a single device.
The Cortex-A15 design has a superior CPU and includes a faster pipe for exchange of data inside chips. Chips based on two Cortex-A15 cores will offer adequate performance, Goren said.
"A quad [Cortex] A15, in this generation, will not be able to even get enough data from the memory. To feed such a beast, you need more advanced memory technologies, you need wider buses. My point is that you need to build those devices that are balanced. You can't just put something huge in the middle but give it a tiny pipe to [access] memory. It will never manifest its performance," Goren said.
Software is also a concern as many current mobile applications are best executed over single or dual-core processors.
"When you look at the total performance, the market is going to speak between multithreaded applications and single threaded applications," Goren said. It will take a couple of years for applications to move to the multithreaded approach, he added.
ARM processors are found in most smartphones and tablets, and are more power-efficient than Intel's Atom chips, which are also making their way into mobile devices. ARM in October introduced Cortex-A7 processors, which can run secondary tasks such as checking e-mail, which typically consume less power. Instead of the real-time OS, Cortex-A7 cores run on the main operating system and are designed to supplement Cortex-A15 cores, which will run high-performance applications.
The new power saving architecture, which ARM calls big.LITTLE, is a right step in delivering balanced and power-friendly chips, Goren said.