Chip makers debate clock frequency, architecture in apps processors

Mike Clendennin
(11/18/2004 8:30 AM EST)

  HONG KONG — As 3G services begin a slow global ramp-up, a handful of chip makers debated the need to push cell phone applications processors into the gigahertz range at the 3G World Congress here this week.

Intel Corp., Texas Instruments Inc. and Qualcomm Inc. agreed that cell phones and smart phones with features such as MP3 players, 5-megapixel cameras and digital TV tuners would need more muscle. But they took slightly differing views on how much is enough.

"The theoretical maximum is already 1-GHz, so what's to say it can't go beyond that," said Luis Pineda, vice president of product management for Qualcomm. "Running up clock speeds to support growing applications is a key aspect, but we need to balance that with smart power management, such as putting specific cores in sleep mode."

During the past two years, Intel has jealousy eyed the sockets of communications specialists like TI, and has made progress in winning designs in PDAs and smart phones. Most recently, it nabbed the applications processor slot away from TI in PalmOne's popular Treo 600 series, putting a 400-MHz Xscale processor into a slot previously occupied by an OMAP running at 133 MHz.

"A lot of the trends we have seen in general microprocessor development in the desktop and server space foreshadow what we are seeing in the mobile space in that throughout the years we have always projected the end of Moore's Law and the end of the theoretical maximum," said Jeffrey Krisa, director of market development for the cellular and handheld division at Intel.

"We as an industry will continue to overcome the challenges such that the advancement in megahertz capability in mobile phones will continue," he added.

TI, which is in the process of designing in its second generation of application processors, called OMAP 2, is sticking with the belief that more megahertz doesn't always equal more performance, especially in the mobile space.

"It's one of the biggest myths," said Jeff Wender, marketing manager for OMAP processors. "There are wide ranges of alternatives — and actually preferred architectures — that allow us to get better overall performance with optimized processors."

Wender cited many of the phones used with NTT Docomo's FOMA 3G service, which use OMAP processors and are generally considered to be pioneering devices when it comes to multimedia capability.

"The way we have been able to offer that premium level of performance while also keeping a watchful eye on power efficiency is with the dual-core architecture. It leverages a general purpose processor with a DSP that can perform some very highly specific tasks in the areas of multimedia in ways that doesn't necessarily require high megahertz," Wender said.

In OMAP, Wender noted that the video and imaging core runs at just 66 MHz. "But it has a very well optimized set of gates," he said. "So what we have chosen is a multiprocessing architecture that smartly manages the level of performance but doesn't mean we have to run it at high megahertz. You can't attach a big fan on the back of this thing to ensure a good user experience."

Krisa agreed that multicore processing would continue to be a trend. "One thing we are starting to see on the desktop PC is using other elements of technology to further the experience rather than just frequency, such as multi-core processing. We'll see that same thing in the mobile space as well."

Still, Krisa indicated that megahertz is an increasingly important factor in the mobile space, downplaying Wender's myth theory. "That's something a company would say that doesn't have a lot of experience with megahertz," Krisa said.