News

First GHz ARM11 chips won't ship this year -or next.

To listen to some of the comment on the new ARM11 processor design "breaking the gigaherz barrier" you might be forgiven for imagining that you will see gigaherz portable phones in your Xmas stocking list. You won't. You probably won't even see them in your 2003 stocking.

The first ARM11 processors may just conceivably appear this year; but when ARM says "The first CPU using the ARM11 microarchitecture will be publicly announced and released to licensees in Q4 2002," the word "implementation" doesn't mean a chip, and it doesn't mean 1,000 MHz.

What it actually means is that ARM is releasing something that will be text; a high level language, a recipe. You might like to think of as "source code" written in a language like Verilog Hardware Description Language - a program which, given time and hard work, people like Intel, Motorola, Agere and Texas Instruments can turn into silicon - some time in 2003.

Next, the first chip certainly won't run at 1,000 MHz. And I wouldn't bet very much of my own money on the proposition that the first 1 GHz ARM11 would ship in 2003 at all - though John Rayfield, head of R&D at ARM will not rule that possibility out entirely.

But the first versions of the ARM11 are designed to run on 0.13µm silicon geometry. That's going to be the standard advanced silicon format for the next couple of years; and on that size features, ARM11 will run at 350 MHz to 500 MHz.

It can get up to nearly 1,000 MHz, 1 GHz, when geometries come down to 0.10 µm - and it is quite possible that this can happen next year. "Some of our partners are doing very aggressive things with their roadmaps," said Rayfield. "There could be a 1 GHz chip by the end of 2003." But he refused to be drawn on how likely this was, or who might be first through the gigaherz barrier. More sceptical commentators are likely to point out that even if such a chip is produced, it will be in small test sample numbers for some months while it is debugged and sold. We're probably looking at 2004.

Even if this happens, however, the likelihood of seeing a phone with this chip in has to be taken with a lot of salt. We're not in Intel silicon territory here, where it announces a Pentium III and says it will run at so many megaherz; ARM processors are remarkable for their ability to scale well onto new technologies, and old designs continue to be used.

The main reason you'd want to use an old design on a new silicon technology is that it uses less power, being a simpler design. "If you don't need lots of MHz, you don't spend the power," said Rayfield. "Look at our roadmap; we're still licensing ARM7 to new partners today. It's at the low pwerformance range of what we can do, but it's useful for a huge number of design sockets - Bluetooth is an area where it is very strong."

The cruel fact is that silicon technology doubles its power according to Moore's Law; twice the power every 18 months to two years. But battery technology doesn't.

Intel may have managed to get a Pentium 4 chip running at 2.2GHz; but that chip consumes 70W of power. It would flatten a phone battery in a second. An ARM7 can run at 100 MHz on 0.10 µm geometry; but it can do it all day and pump out a wireless signal across the office at the same time. As an example, Nokia's latest 9210i combination phone/pda uses an ARM chip running at just 40 MHz - and that's twice the clock speed of the original 9210 which runs at 20 MHz. It is quite fast enough to do data processing, even so.

The new ARM11 microarchitecture "implements the ARMv6 instruction set architecture that includes the Thumb® extensions for code density, Jazelleâ„¢ technology for Javaâ„¢ acceleration, ARM DSP extensions, and SIMD (Single Instruction Multiple Data) media processing extensions." This will make it ideal for 2.5 generation phones and 3G phones if they ever get sold. And it will be wonderful for wireless-equipped pocket computers which have to display video from compressed data, or have to encrypt your messages before transmitting them.

But if you want an intelligent wireless headset which will switch from one PC to another when you flick a switch, you'll go for something a lot smaller; and ARM11 won't dominate the industry for years yet. And the gigaherz version won't ship until 2004 in anything you are likely to buy.