Originally posted by: Idontcare
Originally posted by: taltamir
how is it any different than what i7 does? turning off a core that is not in use is ust another way of saying start with them all turned off and turn them on when needed... the i7 already has a method of cutting power completely to an individual core, and does exactly that.
Anyways, sometimes having multiple cores work at lower mhz might consume less power than having one core working at full mhz, so that might also be taken into account. I am sure they have optimizations done to chose how much cores and at what speed to run each one depending on load.
Well the i7 turns off a core only when it is completely unused. If you have two threads, each consuming maybe 10% of a single core's processing ability, then you are going soo two cores fully powered up and running at any given time, each with 10% utilization.
VirtualLarry's idea is to keep just one core on, handling two threads so total utilization would be 20% and intentionally keep the remaining three cores powered down.
Once you reach 4 threads with any given thread having more than around 5% core utilization you will see all four cores fully powered up but no more utilized than the paltry single-digit percentage.
Having lower mhz cores versus higher ones was the idea I posited...as you can move Vcc down as the mhz moves down so your power savings is even further optimized. This was why I suggested they have circuitry that monitors core utilization and dynamically scale the clockspeed such that whatever the processing needs the clockspeed is always low enough (or high enough) such that the utilization is kept somewhere above 90%.
Maybe that means your i7 is running at 400MHz with a Vcc of 0.85V while you surf the web with core utilization showing as 90% in task manager...if power savings were the objective then something like this could be a potential solution.