Power Consumption

[WizardStan]

Also, if you buy a 400W PC Power Supply, that doesn't mean it always eats 400W.
It just says it can provide a MAXIMUM of 400W.
It wouldn't make sense if it would always eat up 400W.
And it's the same here: It can do at least 600 MHz, probably more. But it doesn't mean it necessarily always have to run at that speed.

BTW: If you buy a car that can do an advertised speed of 200km/h, do you ALWAYS intend to drive full speed?

oooh boy, I'm flipping the puck here
The 400W rated PC power supply may not use the full 400W all the time, but if it needs it, it is there. Same with your 200km/h car: if you're on a straight stretch and you hit the gas, you can make it go full out.
You're advertising a CPU as being able to hit 600Mhz, a CPU that can clock itself up or down as needed just like a car, but you're artificially limiting it. The comparison would be a car advertised as being able to go 200km/h, but no matter how long you hold the gas pedal down, it can not exceed 150km/h unless you flip a switch built into the dash board. It can still go 200km/h under the right conditions, it's just that you have to flip the switch first. On the one hand, having that limit prevents you from going faster than 150km/h if you suddenly need it, unless you've hit the switch. On the other hand, having the switch on activates a special turbo boost which uses up a little bit more gas, even when running at normally slow speeds.

 

[laurencevde]

TI has a nice spreadsheet on its site allowing you to determine its power-consumption in a particular situation, based on measurements and estimates.

 

[darkblu]

I wouldn't use the word "ok", just understandable. I can accept that someone (OPT specifically) would see a dimmer switch that can be turned up with ease as fulfilling their advertisement of a light of specific lumens, even if the dimmer switch comes preset to half power (to use an analogy that doesn't involve cars or food)

burn him!

You're advertising a CPU as being able to hit 600Mhz, a CPU that can clock itself up or down as needed just like a car, but you're artificially limiting it. The comparison would be a car advertised as being able to go 200km/h, but no matter how long you hold the gas pedal down, it can not exceed 150km/h unless you flip a switch built into the dash board. It can still go 200km/h under the right conditions, it's just that you have to flip the switch first. On the one hand, having that limit prevents you from going faster than 150km/h if you suddenly need it, unless you've hit the switch. On the other hand, having the switch on activates a special turbo boost which uses up a little bit more gas, even when running at normally slow speeds.

i take it you haven't heard of the bugatti veyron? ; )

 

[Creature XL]

The debate (well my one) is simple. If you go and buy a cpu that is advertised as 3Ghz, you don't expect that it defaults at 2.5 and you overclock it to get it to the advertised speed. That is where the confusion comes from.

Are you living in the past?

My 5 year old AMD Athlon says it is 2GHz. However, Linux decides to clock it at 1GHz and increases the clock to 1.8GHz or 2GHz as it feels appropriate. So WHERE is the problem? This whole segueing is so stupid in my opinion.
And those guys who want to clock it at the highest possible speed regardless, do not have the slightest understanding of how this all works.

cheers


PS: If oyu know the "Quantispeed" marketing shit AMD has done, you might know that my 2GHz Athlon was marketed as 3000+. So, they were implying it is as fast as a 3GHz P4. I am not sure how many customers haven't understand that. And were proudly saying: "My CPU is running at 3GHz!"



EDIT:
@WizardStan:
Not completly correct your 150/200 KmH analogy.
You can set your default speed to 600MHz one time! I think I might even be able to send you a one-liner which sets your desired default speed (well not your desired just 600MHz as that is the advertised speed) at boot up. And I am pretty sure that OPT will do the same.
To adjust your analogy:
You buy the car. First time you sit down in the drivers seat you flip a switch and from that point on it can go to 200MHz all the time.

 

[TitanUranus]

Now don't get all touchy, I'm only asking - not criticising.

Isn't 100 Pandoras a slim amount of "spares" to have in reserve in case a small percentage of the 4000 first batch suffer a malfunction and need replacing? I'd like to think that you'd have 2.5% reserves in case a slight manufacturing defect 'caused a few faulty units to show up AFTER shipping.

Major companies sell brand name laptops with hidden defects that only become apparent after some poor sap has his gonads burned off in a hideous laptop related incident.

I suspect that you have taken these things into account, but are these 100 really the only reserves you have, and if so how long would you be intending to wait after the first batch has shipped before declaring them superfluous?

 

[Kangal]

To adjust your analogy:
You buy the car. First time you sit down in the drivers seat you flip a switch and from that point on it can go to 200MHz all the time.

One fast car! B)

 

[Monk]

If you go and buy a CPU for your computer, you can't change its max clock speed with the flip of a switch while it's running.

Yes, I can. I have been able to since my first 286 motherboard, where I had a "Turbo" button on the case to let me switch between 8MHz and 12MHz, I can on my current quad-core Intel beastie which also has a "Turbo" button capability built into the power switch (quick-press = Turbo Mode if I want it configured that way).


{other petty wrangling snipped}

 

[WizardStan]

Yes, I can. I have been able to since my first 286 motherboard, where I had a "Turbo" button on the case to let me switch between 8MHz ans 12MHz, I can on my curremt quad-core Intel beastie which also has a "Turbo" button capability built into the power switch (quick-press = Turbo Mode if I want it configured that way).

touché

 

[1magus]

The debate (well my one) is simple. If you go and buy a cpu that is advertised as 3Ghz, you don't expect that it defaults at 2.5 and you overclock it to get it to the advertised speed. That is where the confusion comes from.

Specs are there to tell you what your getting, otherwise why even put a speed on there?

I guess this could just be a semantics/point of view thing.

Okay. It's really easy, actually.
We assure that ALL Pandoras do run at least with 600MHz and most even higher.
That's what 600+ means.

However, it still doesn't make sense using a higher default clock if the OS runs fine with a lower one. It wouldn't make things faster but eat more battery.

Also, if you buy a 400W PC Power Supply, that doesn't mean it always eats 400W.
It just says it can provide a MAXIMUM of 400W.
It wouldn't make sense if it would always eat up 400W.
And it's the same here: It can do at least 600 MHz, probably more. But it doesn't mean it necessarily always have to run at that speed.

BTW: If you buy a car that can do an advertised speed of 200km/h, do you ALWAYS intend to drive full speed?

But how can running the OS @600 not make things faster over 500? It would make tasks run faster, if not than something is wrong there.

 

[juniorm33]

If you go and buy a CPU for your computer, you can't change its max clock speed with the flip of a switch while it's running.

Yes, I can. I have been able to since my first 286 motherboard, where I had a "Turbo" button on the case to let me switch between 8MHz ans 12MHz, I can on my curremt quad-core Intel beastie which also has a "Turbo" button capability built into the power switch (quick-press = Turbo Mode if I want it configured that way).


{other petty wrangling snipped}

Good Old turbo button, how I remember that so well. :lol:

Didn't bother reading thread as I thought it was going down hill quickly, but surprisingly it's not that bad.

Trouble with car and psu analogy is that their figures are the max not the default speed and recognised as such.

I fully understand what ED is trying to say, it's just that it's not the standard way cpu speed is advertised, hence why people always says wait it says 600 on the site. That was all I was pointing out (although others have raised their own issues/queries), and I was saying it could not only be clearer but more impressively described. imo and that's all it is. Nothing to get worked up over.

As for what age I'm living in, well I disable things like speedstep etc on my machines if that's what your on about. It's not always as beneficial as people believe.
Amd's marketing was confusing too many people (and probably meant to be, but I understand why they did it) which as I said is meant to be an equivalent speed not the actual speed the chip was running at.
Although not sure where it relates to this conversation, we're not saying 500Mhz is equivalent to 600Mhz. Or do you mean "well that's just marketing for you"?

 

[paddy]

Ed's post to me was vague ,the way i understand it is 500mhz = 500mhz for apps and stuff full stop ,600mhz should be 600mhz so faster all round ,i didn't know linux will/can automaticly use some kind of cpu speed throttling to adjust when needed ,i also don't like the sound of this as it takes all the control out the users hands so i am asking can i have a basic old style clocking feature without these quirks ? say i want to max the core clock and i can go up to 720mhz from boot up ,i want that for sure and i want it done via the kernal/bios not software so i know the actual hardware is running at that speed all of the time ,this means faster boot times as well as faster os overall and also when not using the default os and using some new software on boot up i don't need to always reconfig or code this in.

This just seems really easy to me ,prolly to easy and simple

 

[WizardStan]

Actually, now that I think of it, there is one very good reason that I can think of to make 500Mhz the default: that is the power-on default of the OMAP. No matter what you set it to while it's running, if you power it off and turn it back on, it reverts back to 500Mhz. This was a decision of TI, not OPT. To get it to be 600 (or higher) you need to add something to the start script to set it on boot.

@Paddy: There is no "kernel/bios vs software" speed thing. There's a register in the OMAP that controls its max speed, but that gets reset when it is powered off. All you do is run software to set this value. As far as I know, it must be done every time you reboot; it doesn't remember the setting between boots and always defaults back to 500Mhz. Fortunately it's easy to add this very simple command to the start script (or at least it should be). Unfortunately it wouldn't be able to do that before it's booted much of the way through, so you won't really see faster boot times. This is actually a very useful feature! Suppose you clock it to 800Mhz and it is fine for now, but a year from now, the circuits have worn just a little bit, and now it's unstable at 800Mhz (exaggerated example!!). If the "bios" (which doesn't really exist, but we'll call it that since it's the term you're most familiar with) defaults to 800Mhz as soon as it's powered on, it would no longer be able to boot at all because it isn't stable enough at 800Mhz anymore. Thankfully, in reality it boots to 500Mhz and, at worst, it crashes when the OS loads. The solution is to simply pop the default OS onto an SD card, use that to boot up into 500Mhz default, and then adjust your startup script in NAND so it only overclocks to 720Mhz instead of 800Mhz now.

Further, you won't really see faster run times if it is set to 720Mhz vs, say, 100Mhz if your CPU is idle 90% of the time anyway. I think that's what ED is talking about when he says you won't see a difference. When not really doing anything, just browsing around the OS or doing some other very simple task, the CPU is 99% idle anyway, so if you bump it from 500Mhz to 600Mhz, that's just an extra 100 million instructions (more or less) that the idle process wastes every second. Why waste those cycles (which take power to execute, even when they aren't actually doing anything) when you can just clock the CPU down and save battery power?
Of course, the OMAP can be clocked down while it's running almost automatically, so if your CPU is 99% idle, it can slow way down (I was apparently wrong about the mechanism by which it does this, so I'll not explain it) until the CPU is more like 50% idle, and uses much less power without you noticing that it is going any slower. Then, as soon as something more demanding starts running, within a second it ramps everything back up to full speed, whether that be 500, 600, or 720.

 

[paddy]

Thanks for all this info WizardStan as i do appreciate it ,in regards to the cpu speed non noticeable in the os at speeds of 500 or 600 or higher ,now im mainly a windows user ,i can tell you there is a big difference when running any windows desktop at say 400mhz or 700mhz even when only clicking on the start button there is a difference you can even see the difference by just moving/dragging an open window so the graphics performance can suffer as well,i know you know this ,so why would the pandora be soo different and almost immune to this.

you can almost feel the slowness and visaversa feel the fluidity when overclocking on a desktop so this is why i wanted to always be running at the max speed ,i don't care much for battery or long cpu life.

ps ,i hope you don't get mad at me for asking these questions ,i really don't know much about arm cpus or the workings of linux with such cpus ,it would be great for me in my eyes to have a constant high end speed but if it can't be done then that is fine but i just want to know and your the man to ask.

i think this prolly answers my question below ...


Mind when we are talking about low cpu speeds this is all apparent ,high speeds like say 700mhz thru 900mhz you wouldn't see a difference like you and Ed say ,but we are talking about low speeds on the pandora and i just can't imagine an os running fine on 500mhz but again i am mainly a windows user so mabe the difference is in fact linux being able to cope much better at low cpu speeds.

 

[WizardStan]

you can even see the difference by just moving/dragging an open window so the graphics performance can suffer as well,i know you know this ,so why would the pandora be soo different and almost immune to this.

Actually, no I can't. Granted, I've had issues with the start button, but that's because it periodically needs to load the items off the hard drive for some reason (seriously, I don't get it. I hit Start, the hard drive goes crazy for 3 or 4 seconds, and then the menu pops up. What's the deal with that?)
At least not on Win2K. Whether I was running it on my 500Mhz or my 2.4Ghz quad core, basic operations were always fluid so long as the CPU was idle (discounting when it would suddenly grab the hard drive. Seriously, WTF Microsoft? Is the start menu so large that you can't just keep it in memory?). It doesn't make any sense why you would see that.

edit: Actually, even if it was doing that, if moving windows around really did take so much CPU that it was noticeable, then the governor would shut off and the CPU would just ramp back up to full speed anyway, so you wouldn't experience the slowdowns.

ps ,i hope you don't get mad at me for asking these questions ,i really don't know much about arm cpus or the workings of linux with such cpus ,it would be great for me in my eyes to have a constant high end speed but if it can't be done then that is fine but i just want to know and your the man to ask.

Oh, it totally can be done, if that's what you want. You can set the max CPU to whatever you want in the boot script and turn off CPU scaling, too, so it just sits there at full power.

 

[Javacat]

I'm going to play dumb now, but if the system scales the voltage/frequency (as several people implied earlier in the thread) depending on demand, and if the CPU is set to 600mhz as default AND taking into account that it apparently doesn't need that (according to ED), then it will surely not go up to that speed anyway so no need to worry and may just hang around 400-500mhz as required. If it does clock up to 600mhz automatically then it means that it needs it, in which case it's there.

That's assuming that ED is right about the OS not needing the extra mhz and that the scaling works properly, which I doubt for both of those. I'm betting that the CPU usage will be higher than people are expecting and any scaling (if any) will be shite.




Psst, please tear this post to shreds if you know what you're talking about. I'm interested in this whole power consumption and clocking thing for the Pandora

 

[paddy]

WizardStan ,i edit in my last post as i think i figured it out ,yes you are right about the harddrive activity and when you clock higher this seems to faster in my experience ,also dragging windows and general small tasks like opening windows doc ,paint and other stuff.

And now you say i can do overclock and turn off the scaling ,you have made my day err night thanks man.

ps WizardStan - m8 you should get a Pandora Knight Hood or something for all the great work you put in on these forums putting up with the likes of me and my febble questions ,you do OPT proud i am sure and i wish more folks were as helpfull and non judgmental as you ,cheers m8.

 

[WizardStan]

That's assuming that ED is right about the OS not needing the extra mhz and that the scaling works properly, which I doubt for both of those. I'm betting that the CPU usage will be higher than people are expecting and any scaling (if any) will be shite.

Well, my BeagleBoard (same CPU) runs at 500Mhz with Pidgin, Midori, irrsi, rtorrent, a bunch of other misc stuff (sshd and apache, etc...), with 95% idle time, so I don't think we'll have a problem.
Sadly I'm lazy and haven't bothered to build the CPU scaling stuff into my kernel, so it's stuck there.

 

[Elanzer]

With the Nokia N900 out of the box it clocks down to 250mhz when not under much load, and only runs at 600mhz when actively loaded. It's possible to reduce the idle frequency further to 125mhz, but this is counter productive (on the N900/Maemo atleast) because the background load will trigger the 50% CPU usage threshold too often @ 125mhz where it deems it necessary to clock the frequency up to 500-600mhz, so instead of constantly running at 250mhz it will keep bouncing between 125mhz and 500-600mhz. 125mhz would work well if the threshold settings actually worked on the N900, trying to make it 75%-80% CPU load before the CPU deems it necessary to step up the frequency doesn't work.

The Pandora will likely be optimally configured in a similar way with CPU governors, it's a basic function of Linux and the hardware inside the Pandora. We don't WANT it running at 600mhz all the time, it's greatly beneficial to reduce the CPU speed low as possible when the system is idle, the voltages and DSP frequency are also reduced at the same time and the CPU will just ramp up when it's required anyways.

It's even more important when overclocking. On my N900 I still get over 35 hours of typical battery life with the CPU clocked at 1100mhz with the puny 1320mAh battery (versus Pandora's towering 4200mAh battery), because it's only at that overclocked frequency maybe 2% of the time - for the other 98% of the time the device is mostly idle the CPU power drain is the same. It doesn't need to be at 1100mhz when I'm sitting there reading a webpage when 250mhz will do the job equally as fast, there's virtually no benefit performance wise of forcing the CPU to it's max speed all the time when you're not using it.

 

[gp32rich]

I'm wondering what the draw is when playing mp3's with the screen off

Even to the point of having a bootable SD with just a mp3 player & no screen driver :lol: B)

 

[WizardStan]

Yes, I can. I have been able to since my first 286 motherboard, where I had a "Turbo" button on the case to let me switch between 8MHz ans 12MHz, I can on my current quad-core Intel beastie which also has a "Turbo" button capability built into the power switch (quick-press = Turbo Mode if I want it configured that way).

I think I came up with a counter argument. Tell me if this works.
If that 286 were advertised as being a 12Mhz computer, but came from the factory with the turbo button off but the manual saying "to get a speed boost, push the turbo button", would you complain to the company about false or at least faulty advertising, or have they still done right by supplying you a 12Mhz processor, even if you have to hit a button to make it active first?