IBM Creates World's Fastest Semiconductor Circuits

Todd Heidesch writes: "'IBM announced it has created the world's fastest semiconductor circuit, operating at speeds of over 110 GigaHertz (GHz) and processing an electrical signal in 4.3 trillionths of a second.' IBM expects the new technology to be pumping out 100 gigabit/sec network switching chips by the end of the year (on an optimistic schedule, I presume)." dr_zeus contributes a link to this Reuters article running on Wired (also fairly thin) on the release, writing: "Granted, this isn't a PC chip, but one wonders how long it will be before we hear 'dude, you've got a 110GHz Dell!'"

Comments

Hitting the Physical Limits

[mikeplokta]

At 110GHz, light travels less than 3mm in one clock cycle -- less than the width of the processor, I presume. And if it's accessing memory from a RAM chip 10cm away, it'll be waiting close to a hundred clock cycles to get anything back.

Re:Hitting the Physical Limits

[taniwha]

actually on cu/si waveguides (ie normal wires on a die) it's way slower than that.

Even at today's high-end speeds (2GHz) 100 cycles (50nS) is fast for dram access. This is why keeping fast chips stoked these days requires heavy caching (L1/2/even 3 on-chip is a must and heading for 50% plus of die area)

The real power of these chips

[Steveftoth]

is in their ability to save power. From what IBM is saying, is that their chips can be run at say only 20 - 40 ghz and consume a hundred times less power then a chip built with todays processes. So you'll be able to get the same or more processing power out of these chips for less enegry.
At 110 ghz, a PHOTON only moves 2.7mm so figure that the actual signal propagation is like 2/3 the speed of that and you see that the signal can only travel 1.8mm in a clock. So, these chips are not going to be all that great for CPUs at 110 Ghz. Much better for signal processing likein routers or something.

4.3 x 10-12 sec

[crumbz]

That means ~1.29mm at C (speed of light), so about 0.9mm in reality. Wow, those better be some short circuit traces!

Wires

[vlad_petric]

Well, don't expect a Pentium 110GHz yet ... The problem with microprocessor design is more and more the time it takes the signal to propagate through wires than the time to propagate through gates.

Did you know that P4 has a couple of pipeline stages that do nothing but propagate signal? (yes, they pipelined the wire ...)

The Raven

Re:Real EEs please enlighten us

[dmlb]

Okay, so I'm a real EE who design in IBM SiGe processes 5HP and 6HP.

1) IBM did demonstrate a ring oscillator.

2) These are IBMs latest SiGe HBT transistors, targetted for the "8HP" process. At present, 5HP and 6HP are in production and producing ICs - a lot of GSM cell phones will have IBM silicon in them. 7HP is coming on line.

3) Yup - these process are not directly for PC processors. The processes are targetted at RF, electro-optical, high speed data etc. They have SiGe transistors and CMOS. The SiGe is typcially used as a front-end, e.g. 10gigabit mutliplexers and laser driver/demultiplexors and diode detectors for optical links and the CMOS does the back end processing - e.g. line equalization etc.

In addition, this is not the fastest semiconductor circuit. For many years people have been using semiconductors at tera-Hz for microwave stuff (granted maybe not ring oscillators but certainly parametric-active amplifiers). I worked on 94GHz radar systems over 10yrs ago that used active semiconductors (IMPATT and Gunn GaAs oscillators).