Rattner Shows off Near Threshold Voltage Intel Architecture CPUby Anand Lal Shimpi on September 15, 2011 1:34 PM EST
Most modern day Intel CPUs run at or above 1V depending on clock speed. For years we had seen decreasing core voltages as Intel transitioned to lower power manufacturing processes, however in recent history it has remained almost flat. While actual transistor switching happens well below 1V, it's very difficult to accurately detect transistor state (off or on) at such low voltages. At what point are you measuring an actual switch vs. just noise? By mapping your high (or on) signal to higher voltages it's easier to tell when the transistor is actually on (e.g. 1V looks very different than 400mV, while 500mV doesn't).
Intel has done a lot of research into running CPUs near their threshold voltage (NTV), the actual voltage at which transistors begin conducting current. There's a lot of work that has to be done to make this happen but the end result is you get tremendous power savings. The chip Intel showed off today can run at less than 10mV (presumably when idle) and operate somewhere in the 400 - 500mV range when higher performance is needed.
In testing NTV Intel turned to its original Pentium architecture for the basis of the chip. The result was a chip that didn't require any heatsink to operate. This NVT Pentium won't be productized but the research will be used for future Intel many-core and ultra-mobile CPUs. Operating at lower voltages is important to both ends of the spectrum - whether you have dozens of cores or a handful of them in a phone, NTV operation would result in huge performance or battery life gains.