So it seems like the program if so coded can take advantage of speeding up a processor clock speed to optimize demand vs. power draw etc... Well on my current batch going the CPU usage looks lower on the display but the percentage is higher no more like 1,750% CPU. One difference is this encode using parallel encode all the simultaneous files are H_264 and before it was a combo of ProResHQ and H_264. Perhaps the way the processing works for H_264 meshes better with other tasks with the same codec. Just guessing.
Here's the stuff fueling my nerd gasim:
Running a processor at high clock speeds allows for better performance. However, when the same processor is run at a lower frequency (speed), it generates less heat and consumes less power. In many cases, the core voltage can also be reduced, further reducing power consumption and heat generation. By using SpeedStep, users can select the balance of power conservation and performance that best suits them, or even change the clock speed dynamically as the processor burden changes.
The power consumed by a CPU with a capacitance C, running at frequency f and voltage V is approximately:[3]
- P = C V 2 f {\displaystyle P=CV^{2}f}
For a given processor, C is a fixed value. However, V and f can vary considerably. For example, for a 1.6 GHz Pentium M, the clock frequency can be stepped down in 200 MHz decrements over the range from 1.6 to 0.6 GHz. At the same time, the voltage requirement decreases from 1.484 to 0.956 V. The result is that the power consumption theoretically goes down by a factor of 6.4. In practice, the effect may be smaller because some CPU instructions use less energy per tick of the CPU clock than others. For example, when an operating system is not busy, it tends to issue x86 halt (HLT) instructions, which suspend operation of parts of the CPU for a time period, so it uses less energy per tick of the CPU clock than when executing productive instructions in its normal state. For a given rate of work, a CPU running at a higher clock rate will execute a greater proportion of HLT instructions. The simple equation which relates power, voltage and frequency above also does not take into account the static power consumption of the CPU. This tends not to change with frequency, but does change with temperature and voltage. Hot electrons, and electrons exposed to a stronger electric field are more likely to migrate across a gate as "gate leakage" current, leading to an increase in static power consumption.
Older processors such as the Pentium 4-M, which use older versions of SpeedStep, have fewer clock-speed increments. SpeedStep technology is partly responsible for the reduced power consumption of Intel's Pentium M processor, part of the Centrino brand.
---In Avid-L2@yahoogroups.com, <mactvman@...> wrote :
You raise an interesting point. I wonder if some of the difficulty in comparing using the visual core display is weather or not it reflects speed stepping in the cores.
I recall that the only thing that makes my Mac Pro 12 core get up and run full tilt, with the cooling fans winding up to high speed is Sorenson Squeeze (R.I.P.). An interesting side note is that Squeeze was always only 32 bit. But boy could it get my machine cranking on an encode.
I don't have Adobe Encoder to compare since I let my subscription lapse a few years ago after the umpteenth time they tried to jack the price up on me. Don't really miss it except for photoshop, which I replaced with GIMP and GraphicConverter.
But probably the issue is CPU speed stepping.
Dave Hogan
Burbank, CA
For the fun I often open Acitvity Monitor when transcoding or other processor intensive processes to see how much of the 12 core is being used.
I can get up to 2,000 percent usage on Avid Transcodes depending on the codec and perhaps other factors I'm unaware of. Today it CC 2015 Adobe Media Encoder and the CPU Usage window is screaming with all 24 bars up to the top. The second bar of the core hyper thread is just a little below top and the first bars are all to the top. My visual math would suggest approx 2,100 cpu percentage but in the Activity monitor window the %CPU is bouncing around 1,400 to 1,600 %CPU. Curious why CPU Usage bars look like more core is being used? IIRC with Avid it's more visually bar graph and %CPU comparable. Is there something about how AME processes that would cause the perceived discrepancy. I am running parallel encoding with ProResHQ and 2 H_264 encodes for each file. Not a broke but makes me curious.
John Moore Barking Trout Productions Studio City, CA
bigfish@...
