Discussion in 'Article Discussion' started by bit-tech, 14 Mar 2018.
"meaning the Pi 3 B+ is as fast while undergoing thermal throttling as the Pi 3 is at cold."
other way round, no?
No? The Pi 3 B+ starts at 1.4GHz and throttles to 1.2GHz; the Pi 3 starts at 1.2GHz and throttles to sub-1GHz. So: the Pi 3 B+ is as fast while undergoing thermal throttling as the Pi 3 is at cold.
ah, with you now. It's the idea of choosing between a cold CPU running at 1.2 or a hot throttled CPU running at 1.2 that's getting me confused, as I'd choose the former. But then I'm also used to cooling things to the extent that i view throttling as a symptom of a fault.
I think I must be explaining this badly, sorry.
Take a Pi 3 and a Pi 3 B+. Turn them on.
The Pi 3 is running at 1.2GHz. The Pi 3 B+ is running at 1.4GHz.
Run a CPU-intensive application. Wait for the processors to get hot.
The Pi 3 is now throttled to sub-1GHz. The Pi 3 B+ is now throttled to 1.2GHz.
You don't get to 'choose' a cold CPU, unless you don't actually use it. What you can choose is a CPU which runs at 1.2GHz for a bit and then drops to sub-1GHz, or a CPU which runs at 1.4GHz for a bit and then drops to 1.2GHz.
If you put active cooling on both models, the Pi 3 will run at 1.2GHz without throttling and the Pi 3 B+ at 1.4GHz without throttling.
i got you at the second time round; it was the wording 'the Pi 3 B+ is as fast while undergoing thermal throttling as the Pi 3 is at cold' that made my mind think 'two processors, same speed, new one is hot and throttling while old one isn't', but that perspective disregards that the old one is effectively idle while the new one is under load in that comparison. My mind didn't equate 'cold' with 'idle', and i usually view 'cold' as being a good thing.
I could probably have phrased that bit better. In my defence, it was written at o-dark-hundred last night and I was well into the rum by then...
say no more #rumlife
I wonder if they changed the position of any of the connectors. I have an acrylic case made for the Pi2B that I wonder if it will fit the Pi3B+.
With the new packaging, does it require new heatsinks? I have an unused aluminum one and I'm wondering if it can be attached and if it covers the entire heatspreader.
Fits perfectly: the overall design hasn't changed since then. The only change is the addition of the pre-fitted PoE header, which has shifted the unpopulated run header down a bit - can cause problems with some HATs, but not cases.
It'll fit fine, though will overhang slightly: the raised surface of the heatspreader is smaller than the old plastic package.
I see. So if you want PoE you can't use a heatsink. There's that fan though. Here's to hoping it's not a whiny little PoC!
...yes, you can? A properly-sized heatsink (i.e. one that isn't too tall) will fit fine under the PoE HAT, as far as I'm aware - just as it would under any other HAT. That's not a Pi 3 B+ or a PoE HAT thing, that's just a Raspberry Pi thing and has been since the first add-on board came out for the original 24-pin GPIO header.
So probably the second in this list would fit, but not the third and fourth.
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