Modest and safe overclocking of Pi 3 B? Warranty concern?

Wizardling

G'day.

I'm running RetroPie on my new Pi 3 model B, and BOINC during gaming downtime. I'd like to get a wee bit more performance with emulation of newer classic consoles, and it certainly cannot hurt to process SETI@home work units faster, eh? But I don't want to go overboard. And I don't want to void my warranty. Killing my first ever Pi would be a bit disappointing. I know it's cheap-as, but still. I want to play it conservatively with my first Pi overclock.

So, can someone suggest some solid and modest overclock settings for the /boot/config.txt file, please? Helpful would be, say, one step up from base speeds, and then another couple steps up. But despite running a copper CPU heatsink and 3cm fan, I don't want to go crazy here. Not at first, and not without a backup unit on hand, anyway.

TIA :-)

drake999

If modest overclocking settings for emulation is what you are looking for, I recommend you don't bother overclocking the CPU at all, but rather overclock the memory, GPU, and possibly the SD card reader. If you use the following settings, emulators should benefit. I find most emulators don't max out even a single ARM core on the stock clock speed. It's the GPU heavy emulators that seem to suffer.

arm_freq=1200
core_freq=500
gpu_freq=500
sdram_freq=500
over_voltage=2
dtoverlay=sdhost,overclock_50=100
temp_limit=85
avoid_warnings=1

With these settings you should be OK with open air cooling provided you have a heatsink. If you go beyond these values, you will likely need active cooling to maintain stability. Also a word of caution, I've recently became aware that for some reason the SD card overclock disables the wifi, if you are using Ethernet you may not be concerned about this, but if you are using wireless you may want to leave the SD card overclock out. I can only speculate why this is but if I were to guess I'd say the SD card reader and WiFi module likely share the same bus or something.

drake999

@Wizardling I should also explain the "avoid_warnings=1" settings. Basically this prevents the system from displaying power or thermal warnings onscreen. I disabled it with this setting because sometimes during a game it would approach the thermal limit and a red box would appear onscreen. I knew the system would downclock itself when it reached the thermal limit anyway so I didn't want the warning onscreen. However if you do want the warnings (and since this is your first Pi I imagine you might) just leave the avoid_warnings=1 line out.

Wizardling

Thanks :-) I am using WiFi, so I'll watch out for that 'gotcha'.

Say, in what increments can I step up the speed of each part? Or can I just pick any likely modest increase and try it?

drake999

@Wizardling I should add that this wifi glitch that I've recently become aware of may not be universal across firmware versions. It may work for you so it may be worth testing. As far as your increments question, I think I've seen people use 525 MHz and 550 MHz for GPU and RAM but not much beyond that. I have also seen RAM clocked at 600 MHz before. I generally don't go above 500 MHz as I usually favor caution and guaranteed stability, but now that I have active cooling I may get bolder in the near future. I'm sure there are others on this forum that can advise you better than I can about pushing the limits of the Pi3.

Wizardling

@drake999 Well, I'll save pushing the limits for later on in my Pi usage :-) For now I just want to test the waters and dabble with one or two increments speed increase.

drake999

@Wizardling I may have misunderstood your question as I now realize you may have been referring to increments below my recommended 500 MHz. I don't believe it is necessary to employ increments below the 500 MHz I recommended as the VideoCore IV GPU and the RAM are well known to be able to take these clocks, and in previous generations these figures were in the supported overclocking settings. Basically you are safe to go right to 500 MHz unless you have a manufacturing defect of some kind in my opinion.

Wizardling

@drake999 Yeah, you're right, I was. But if 500MHz is considered safe, I'll try that, thanks mate :-)

I reckon I'll avoid the SD card for now. I want to play it safe. I'll just go for increasing graphics performance as you suggest, plus CPU to 1300 I reckon, to give BOINC a wee boost. I've heatsinks everywhere but the memory chip (I didn't realise my case would have room) for now, and a 5V fan running in the top of my case.

drake999

@Wizardling Glad I could help. That 5V fan should keep things nice and stable at 1300 MHz. I do not recommend overclocking the CPU at all without active cooling, but sounds like you have that covered. Best of luck to you in your experimentation friend.