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2010-07-04
, 10:13
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Posts: 105 |
Thanked: 56 times |
Joined on Apr 2010
@ Florida
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#2
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I've read the official wiki page on OCing, and a number of posts on N900 overclocking, and I'm wondering a couple of things:
One, has anyone actually killed their device by OCing for an extended period of time? (Though, it may be too soon to tell, seeing as its only been released for 9 months or so.
Also, has anyone done any speed/lifetime calculations as to what the lifetime should be?
Two, Why is the A8 in our Nokia N900s clocked to 600mhz by default, when ARM's site says they can run from 600mhz-1ghz, and other A8-based devices on the market use ~1ghz clocks? Are these other devices using a different chip, or was the Nokia simply factory underclocked to reduce power usage(or reduce heatsink requirements)?
If the latter is the case, it would seem to be perfectly safe to OC to 900mhz-1ghz(provided voltages are appropriately adjusted,), as the chip is designed to have a good lifetime at those speeds.
Am I correct in any of this, or do I not know what I'm talking about?
Thanks,
-Rob
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2010-07-04
, 10:25
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Posts: 2,473 |
Thanked: 12,265 times |
Joined on Oct 2009
@ Jerusalem, PS/IL
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#3
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2010-07-04
, 10:32
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Posts: 726 |
Thanked: 345 times |
Joined on Apr 2010
@ Sweden
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#4
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What annoys me though, is that apps like CPUFreqUI to report "raw" speeds, using a sensor that according to SpeedEvil, TI themselves suggest not using, and it's not on the CPU, it's next to the battery.
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2010-07-04
, 10:34
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Posts: 1,224 |
Thanked: 1,763 times |
Joined on Jul 2007
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#5
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Based on what I know.
The chip in the N900 should run @ 550, with 600 being a default "overclock".
Running 550 gives the device a lifetime of 10 years.
600 5 years, that's half the lifetime for a 50MHz increase (rough estimate).
afaik these values are from TI (texas instruments) themselves.
My rough estimes:
650MHz, 2.5 years, 700MHz 1.25... you can guess the rest I suppose.
Also, according to joerg_rw, an engineer (not at Nokia mind you), damage to the CPU occurs due to http://en.wikipedia.org/wiki/Electromigration, not thermal factors.
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2010-07-04
, 10:38
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Posts: 105 |
Thanked: 56 times |
Joined on Apr 2010
@ Florida
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#6
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Based on what I know.
The chip in the N900 should run @ 550, with 600 being a default "overclock".
Running 550 gives the device a lifetime of 10 years.
600 5 years, that's half the lifetime for a 50MHz increase (rough estimate).
afaik these values are from TI (texas instruments) themselves.
My rough estimes:
650MHz, 2.5 years, 700MHz 1.25... you can guess the rest I suppose.
Also, according to joerg_rw, an engineer (not at Nokia mind you), damage to the CPU occurs due to http://en.wikipedia.org/wiki/Electromigration, not thermal factors.
What annoys me though, is that apps like CPUFreqUI to report "raw" speeds, using a sensor that according to SpeedEvil, TI themselves suggest not using, and it's not on the CPU, it's next to the battery.
Anyways, this is the info i've collected so far, what I said above is not from my personal findings (except my rough estimates).
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2010-07-04
, 10:44
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Posts: 2,473 |
Thanked: 12,265 times |
Joined on Oct 2009
@ Jerusalem, PS/IL
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#7
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Isn't this the temperature sensor? That's something else than measuring the frequency, even though higher frequency will give a higher temperature.
Frequency is set as a variable in code, it's not something you measure with a hardware sensor unless you're analysing the CPU protocol.
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2010-07-04
, 10:54
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Posts: 334 |
Thanked: 171 times |
Joined on Dec 2009
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#8
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The sensor is just close to the CPU, it's not on it, plus it sometimes report a value of -40.
@ Matan, so values from TI are meaningless?
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2010-07-04
, 10:56
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Posts: 162 |
Thanked: 24 times |
Joined on Feb 2010
@ Essex, UK
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#9
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2010-07-04
, 10:56
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Posts: 2,802 |
Thanked: 4,491 times |
Joined on Nov 2007
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#10
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when ARM's site says they can run from 600mhz-1ghz, and other A8-based devices on the market use ~1ghz clocks?
One, has anyone actually killed their device by OCing for an extended period of time? (Though, it may be too soon to tell, seeing as its only been released for 9 months or so.
Also, has anyone done any speed/lifetime calculations as to what the lifetime should be?
Two, Why is the A8 in our Nokia N900s clocked to 600mhz by default, when ARM's site says they can run from 600mhz-1ghz, and other A8-based devices on the market use ~1ghz clocks? Are these other devices using a different chip, or was the Nokia simply factory underclocked to reduce power usage(or reduce heatsink requirements)?
If the latter is the case, it would seem to be perfectly safe to OC to 900mhz-1ghz(provided voltages are appropriately adjusted,), as the chip is designed to have a good lifetime at those speeds.
Am I correct in any of this, or do I not know what I'm talking about?
Thanks,
-Rob