Windows 10: my cpu clock speed just broke the sound barrier

submitted by /u/TareqP
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:)

 

CPU Clock speed locked at 0.79GHz

Hi, I have an i7-4500U CPU and for the last few months my system starts at full speed (2.39GHz) but as soon as the CPU goes below 30% utilisation after startup, the system locks the clock speed to 0.79GHz even when the fan is off. The CPU temperature is
around the 50degree C mark, therefore should be allowing the processor to go up to full clock speed.

I've changed the power settings to set the minimum clock speed to 50%, but that has made no difference.

 

CPU Clock speed with Belle Update

I would be surprised if the rest of the hardware in the phone, like the RAM etc, couldn't support the maximum CPU clock speed. When such sophisticated electronic devices are designed it's impossible to know until it's all been put together how it will actually
perform as a complete unit - the hardware, software, battery capacity, etc. The clock speed allows a fine-tuning once everything comes together, to get the optimal balance.

Well-made software makes a huge difference to how much CPU/hardware resources are required. Software efficiency is the most important factor of all.

A GPU is only there to perform tasks that would otherwise take up huge amounts of CPU resources. Dedicated graphical tasks such as 2D scrolling, 3D texture-mapping/filling for example. But that's all. The CPU is still running the whole show, but just has much
of the load taken off it by the GPU.

So with the GPU doing more and more, the CPU and it's speed become less relevant.

 

CPU Clock speed with Belle Update

I'm no great hardware engineer, so can only relay what I've read and my interpretation of that information...



Apparently the N8 (in particular - not sure about other models) is designed from a hardware perspective around the graphics processor and it's capabilities. The idea is that all interaction with the phone is through the display, so there's a dedicated processor
to handle the interpretation and response to anything happening on the screen. The CPU in this design does very little other than actual execution of programs running on the phone. Because those two processors have to communicate in the most optimal fashion
possible, the CPU (although capable of faster speeds) is slowed down to match the graphics processor.



It may seem a silly design decision to slow the CPU down, but when you consider that the graphics processor takes much of the load from the CPU (apparently unlike in other phone designs), then you can understand that the N8 is faster than phones with much
faster CPU's.



The upshot of all this though, is that speeding up the CPU would almost certainly not make the N8 faster (may in fact make it slower as the CPU waits for the graphics processor in mismatched clock cycles). I guess we just have to be impressed by Nokia's
design to get so much more out of a phone with so much less...



Cameron



PS this would be an interesting discussion for one of Nokia's hardware engineers to step into and confirm one way or the other what the impact of changing the CPU speed would be on the N8.