over clocking the pi zero W

[DKeeling]

Hi

Could anyone tell me if its worth over clocking the Pi Zero W and if so how?

Thanks in advanced

[MaxK1]

How much would you have to overclock for you to consider it "worth it"? Don't expect more than about 10% (You may be one of the lucky ones that can push the SoC further, but expect a lot of experimentation and whacked SD cards) Good Luck!

[wouterds]

Very interested in this as well. Would be nice to get it to 1.1Ghz.
Just changing arm_freq to 1100 results in a Pi that doesn't boot anymore, FYI.

[MaxK1]

If you want something faster than raspi-config offers, you have to experiment.

[wouterds]

Update; got it working using following settings (warranty will be voided because force_turbo is used in combination with over_voltage):

Code: Select all

# 10% overclock
arm_freq=1100
over_voltage=8
sdram_freq=500
sdram_over_voltage=2
force_turbo=1
boot_delay=1

[KLL]

thanks for the info,
you use cooler housing venting?
what cpu temperature say?
pls report back after a month if still running!
your post should not give the impression of a well tested setup.

[wouterds]

Temperature is around 50 degrees celcius without any cooling at all and the CPU running at 100%.

[MaxK1]

Pretty good! Let it run for a few days like that. If it doesn't fail, you can try bumping it up to 1150.

[tastycrust]

I looked around a bit on here and didn't see any more recent posts about this, so sorry about reviving an old thread. Did you ever have luck at anything above 1100 for your RPi0? It's just such a shame that it runs so cool at 1100 (rarely cracks 50C at full load for hours on end), but refuses to boot at all at anything above that. Does anyone have any ideas for why that might be? Do some of the other options need to be tweaked at higher clock rates?

[MaxK1]

Not all pi's overclock equally well.

[tastycrust]

Yeah, I'm just confused why it's so stable at 1100 and runs almost cold, but completely refuses to boot for 1150 or 1200.

[Imperf3kt]

I'm guessing its because settings and actual values are different?

I would put money on it that the Pi0 was underclocking to protect the SoC and thus, while set to 1100MHz, was probably only operating at ~600MHz

[MaxK1]

If it was running at 100% it was probably at 1100MHz. 1100 to 1150 may have been too big a jump - try backing down to 1140 or 1130 and put the same load on it (It may boot OK, but fail under load) I would still put a heatsink on it with thermal compound or tape. Or just settle on 1100, sit back and have a beer.

[Imperf3kt]

If it was running at 100% it was probably at 1100MHz.

Not really.
Lets use imaginary numbers for the purpose of demonstration.

Say the Pi0 can compute 1 thing per second at 1100MHz, but it causes 100% CPU load
Its likely to get hot, thus activating the Pi's thermal throttling which brings it down to around 600MHz, roughly half.
You're still trying to process 1 thing per second, but now you have half the power to do it, hence CPU remains at 100% but takes more than twice as long to do the same task because its running at half the clock speed.

[MaxK1]

Easy enough to confirm:

/opt/vc/bin/vcgencmd measure_clock arm

and force:

force_turbo=1 (in /boot/config.txt)

[jamesh]

If it was running at 100% it was probably at 1100MHz.

Not really.
Lets use imaginary numbers for the purpose of demonstration.

Say the Pi0 can compute 1 thing per second at 1100MHz, but it causes 100% CPU load
Its likely to get hot, thus activating the Pi's thermal throttling which brings it down to around 600MHz, roughly half.
You're still trying to process 1 thing per second, but now you have half the power to do it, hence CPU remains at 100% but takes more than twice as long to do the same task because its running at half the clock speed.

The CPU governor if it knows the CPU is running at 100% WILL up the frequency to the max if the CPU is not over hot. And on the Zero you are unlikely to overheat the CPU.

Note that CPU temp is not the (only) reason why the device may not allow you to go over a certain frequency. Itn the case above its nowhere near throttling (50c) but still won't go any faster, this is down to other factors. ie no matter how much you cool, there is a limit to how fast the gates on the chip will run. Cooling will allow faster frequencies, up to a point.

[tastycrust]

I ran the stress package while monitoring both temperatures and actual CPU clock rate, and it stayed at 1100 for a few hours and maxed 52°C, without even so much as a heatsink.

So yeah, there's something going on with this chip that isn't heat-related to cause problems at clock rates over 1100.

[MaxK1]

You got 10% - the law of diminishing returns will kick in beyond that (passive and or active cooling, better (less noisy, etc.) PSU and playing with other timing and possible crash recovery add expense and time. And you still may not get there. As jamesh implied, all it takes is one gate... All overclockers have those decisions to make. On the other hand, it is (or can be) fun to see how far you can push it!

[jamesh]

I ran the stress package while monitoring both temperatures and actual CPU clock rate, and it stayed at 1100 for a few hours and maxed 52°C, without even so much as a heatsink.

So yeah, there's something going on with this chip that isn't heat-related to cause problems at clock rates over 1100.

There's nothing 'going on'. There is simply a limit to how fast chips can go, whatever temperature they get to. If it were entirely down to heat, we would all have 100GHz machines running in freezers, but we don't.

You are running 100Mhz faster than spec, that's not bad at all.

[tastycrust]

Sorry, I just meant that as an agreement with what you said -- "something going on" as in chip failing to work for reasons other than heat. I didn't mean like something wrong or fishy.

[MaxK1]

You could just shell out another $10 and get another one and see if you get one more amenable to overclocking But, be careful, these little things are more habit forming than chocolate covered peanuts.

[tastycrust]

They sure are... right now I"m at:
1 original RPi
1 RPi 3
2 Rpi0 W
~3 other SBCs

And all I can think is I need a few more....

[MaxK1]

Maybe we need a support group or some kind of 12 step program... Or a warning on the package at least!

[HawaiianPi]

The Pi Zero series are already overclocked out of the box. Remember it uses the same SoC as the model A/B/B+ which is clocked at 700MHz. So they are already clocked up at 1GHz and likely won't do much more than that unless you get really lucky with your SoC (there's always a small chance you'll get one that runs at the lower end of the voltage/heat range of manufacturing tolerance).

The problem is that by the time you have purchased enough Pi Zeros to find that prime unit, you could have purchased a Pi3 (or several) which will be much faster no matter how high you manage to clock your Zero.

If your goal is simply to see how high is up, and you don't mind purchasing a bunch of extra Pi Zero computers to find the best overclocker, then by all means, go for it. However, if what you really want is more performance, then just get a Pi3. It's 7-8 times faster than the Pi-Zero and can be overclocked itself for even more.

One of the big problems with overclocking the single core models is that they use pop RAM, which means the RAM chip is mounted on top the SoC, so there is no way to cool the CPU+GPU directly (a heatsink on the main chip package will be cooling the RAM, which really doesn't need cooling). The Pi3B has the RAM on the bottom of the board, so the SoC (CPU+GPU) can be directly cooled, which will often result in better overclocking performance.

Do keep in mind that overclocking by its very nature is running the chip above its design spec, so there is no guarantee any chip can be overclocked. It's all luck of the draw. For everyone who has one of the rare heavy overclockers, there will be someone who has one that won't overclock well (or at all). Bottom line is, don't go into it expecting to be able to overclock, and be prepared for disappointment.

[tastycrust]

In my case, I'm doing some minimal real-time OpenCV image analysis, but need the smaller form factor of the Zero to fit in my project. Overclocking even a little helped increase the frame rate enough to be worth it.