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RockBoy Speed

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grossaffe:
i was simply stating it could be done, but definitely should NOT be done.  first off, i don't know of any way to do it through software (don't know if the rockbox developers could do it), which means it would have to be done with an oscillator crystal soldered to the main board, most likely not fitting in the designed case.  and on top of all of that, like previously stated, it would be a terrible strain on the chip as well of the lack of adequate cooling which would no doubt cause irreparable harm do the device.  but if you REALLY wanted that little performance boost...

Llorean:
It can be done in software fairly easily actually.

Sanek:

--- Quote from: Llorean on December 04, 2007, 09:35:57 PM ---It can be done in software fairly easily actually.

--- End quote ---

Just a little follow-up question:
On an iPod, when CPU frequency increases, does the voltage change with it (proportionally) or is the voltage always constant?

My guess would be that it changes all the time depending on the CPU utilization as to save some energy, but is that really the case?

RockBoy was just an example since thats what the thread was about. The reasoning I had behind the overclocking question is that it would allow running more demanding applications on the same targets, but I guess it could possibly be too dangerous and ultimately not worth the risk to go beyond the specifications of the CPU - which brings me to my next question...


--- Quote from: safetydan on December 04, 2007, 08:23:04 PM ---The specifications that we have for these chips say that their maximum clock is 80 MHz. Do you really want to go outside that? Apart from heat and battery life issues there's also the danger of breaking the CPU in some way.

--- End quote ---

According to Wikipedia, 5th Generation iPods use PortalPlayer 5022 CPU
http://en.wikipedia.org/wiki/PortalPlayer

And according to the PortalPlayer 5022 CPU Specifications in the Rockbox wiki:

--- Quote ---Up to 100 MHz processor operation per core with independent clock-skipping feature on COP
--- End quote ---

http://www.rockbox.org/twiki/bin/viewfile/Main/PortalPlayer?rev=1;filename=5022_Brief_Mar05.pdf

So maybe there really is room for overclocking there?

safetydan:
That's one particular model. Other's in that series support lower clock rates.

As the the clock rate is software controllable, feel free to experiment. But it's something that you're doing at your own risk. A much better solution would be to optimise rockboy.

Llorean:
It's quite likely that, for most things Rockbox does (with the notable exception of Monkey's Audio music, which isn't even fast on the Gigabeat) we should be able to run them successfully at 80mhz with enough optimization.

Since we're going to *have* to do it anyway for most of the iPods, we should focus any effort on solving the problems.

As well, that wikipedia article is slightly wrong. The iPod Video uses the PP5021, which reports itself in software as a PP5022C, and we theorize that those are PP5022 chips that don't run stably at full speed.

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