The 1ghz overclock

[Eridger]

You had me at dynamic clock speed and voltage, good sir.

 

[Poem58]

Most people seem to be excessively worried about overclocking. I will be happy to overclock my 600Mhz-rated Pandora up to 1.2Ghz, but I will do it safely.

I don't usually comment on grave-dig posts but had to correct before anyone else who might be new expected a 720Mhz rated chip when ours has always been rated for 600Mhz. The 720's were added later and not what was purchased for the Pandora. Happy OC'ing!

 

[DoubleDash]

TI specifies the following lifetimes in their docs:

3.3 Recommended Operating Conditions
All OMAP3530/25 modules are used under the operating conditions contained in Table 3-3.


Note: To avoid significant device degradation for commercial temperature OMAP3530/OMAP3525 devices (0°C ≤ Tj ≤ 90°C), the device power-on hours (POH) must be limited to one of the following:


• 100K (11.4 years) total POH when operating across all OPPs and keeping the time spent at OPP5-OPP6 to less than 23K (2.6 years) POH.


• 50K (5.7 years) total POH when operating at OPP5 - OPP6.


• 44K (5 years) total POH with no restrictions to the proportion of these POH at operating points OPP1 - OPP6.


Note: Logic functions and parameter values are not assured out of the range specified in the recommended operating conditions.

Not long enough for you?


With 8 hours/day of power-on-time, it'll last (at full performance) for 15-30 years, depending on how often you play heavy games. I think some other parts will break down long before that...


IIRC, the earlier firmwares could not automatically switch OPP-domains, so it got put at the default OPP3. If I'm not mistaken, it now goes back there when there's no heavy stuff running, so you won't actually be running at OPP5 all the time if you increase the speed.


TI guarantees that the chip can run properly at the specified speeds (500Mhz for OPP3, 600Mhz for OPP5), within certain power constraints, at those performance domains. However, those are worst-case numbers, so the chance that your chip can run significantly higher ( or reach its speeds on a lower OPP) is quite high. Heat isn't really an issue, the complete chip normally consumes <2W at max, which can be easily dispersed. The ARM-core only contributes <500mW to that... The really limiting factor for TI is power consumption. Battery lifetime is, for most mobile devices, more important than pure speed. There's also a slim chance that some transistors aren't able to switch at higher speeds at those voltages (more likely at OPP3), which may cause funny things...


All in all, overclocking is quite safe. The worst thing that can happen is that it'll crash, or cause unstabilities, and power-consumption goes up (and as such, battery-life goes down).

Can someone confirm that the OPP mode scales back automatically when the cpu is in low use? Is the OPP mode a maximum cap but only used at certain cpu speeds. If so how would the omap apply logic to when it changes OPP mode? Just curious, and of course it related again to the potential life span of the pandora.

 

[Natro]

The TI OMAP processors have a power saving functionality that they call "SmartReflex" which is basically a dynamic clock and voltage scaling mechanism... as far as I understand it, the processor will (by default) automatically downscale the processor clock speed (MHz) and voltage levels (OPP settings) depending on the demand at any given time. In other words, even if you were to "overclock" to 1Ghz @ OPP5 and playing a game that only demanded ~600MHz => OPP3 the processor would automatically downscale to the fit the demand. Essentially the "overclock" settings only set the maximum levels that the processor is allowed to go up to but will only use what it needs.


What is not clear to me is how often and rapid the processor assess and changes the clock speed and voltage levels.


The bottom line is..."overclocking" and "overvolting" should not dramatically reduce the lifespan of the processor even when done to the extreme due to the above feature. To quote Douglas Adams... its "Mostly Harmless"...

 

[DoubleDash]

^


Thanks Natro. Exactly what I wanted to know. Also interested in the point you made about how often and by how much.

 

[Mamemeister]

Chaps, am I correct in assuming all this overclocking talk is referring to the original 600mhz Pandora. What would seem to be an acceptable safe speed over 600mhz to run it at without risk of damaging the unit?

 

[TrashyMG]

Holy old thread....


I run mine any where from 800Mhz-1ghz all the time.. the rest of the Pandora will fall apart years before you can destroy it from overclocking it.

 

[Letalis Sonus]

Overclocking by itself has no influence on the hardware, it's the voltage that matters. However, there are only a few fixed voltage levels and none of these are really hitting a limit - combined with the low heat emission of the SoC you simply can't kill it through overclocking, you can only make it wear out a tiny bit faster, which still is a LOT of lifetime.

 

[Mamemeister]

I've been running it at the stock 600mhz since getting it last week, reckon I'll stick it up to about 750mhz.

Really appreciate your prompt help!

 

[WizardStan]

http://boards.openpandora.org/index.php/topic/10086-cpu-stress-test/

Run this, it'll slowly ramp up the clock speed on your Pandora until it starts getting errors, and then start bringing it down again until it is stable. If you leave it running for a few hours it's usually pretty safe to say that the speed it is showing is your safe maximum.

There's really no reason not to run it as fast as it can. When it first came out it didn't have the best power management, so if you increased the clock speed it would increase the voltage and drain out the battery faster, but now all of that is dynamic: it only drains the battery when it's actually doing work, and when it is idle it will go for days between charges.

 

[Mamemeister]

Thanks fella, will give this a go tonight. So basically run it overnight and it will automatically set it at a stable speed?

 

[TrashyMG]

^

It will just give you a recommended stable speed you can set you Pandora to.