1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

News Raspberry Pi 3 B+ launches with new SoC, 5GHz Wi-Fi

Discussion in 'Article Discussion' started by bit-tech, 14 Mar 2018.

  1. bit-tech

    bit-tech Supreme Overlord Staff Administrator

    Joined:
    12 Mar 2001
    Posts:
    1,247
    Likes Received:
    21
    Read more
     
  2. adrock

    adrock Caninus Nervous Rex

    Joined:
    5 Dec 2006
    Posts:
    1,248
    Likes Received:
    41
    "meaning the Pi 3 B+ is as fast while undergoing thermal throttling as the Pi 3 is at cold."

    other way round, no?
     
  3. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

    Joined:
    4 Dec 2007
    Posts:
    10,570
    Likes Received:
    792
    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.
     
  4. adrock

    adrock Caninus Nervous Rex

    Joined:
    5 Dec 2006
    Posts:
    1,248
    Likes Received:
    41
    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.
     
  5. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

    Joined:
    4 Dec 2007
    Posts:
    10,570
    Likes Received:
    792
    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.
     
  6. adrock

    adrock Caninus Nervous Rex

    Joined:
    5 Dec 2006
    Posts:
    1,248
    Likes Received:
    41
    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.
     
  7. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

    Joined:
    4 Dec 2007
    Posts:
    10,570
    Likes Received:
    792
    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...
     
  8. adrock

    adrock Caninus Nervous Rex

    Joined:
    5 Dec 2006
    Posts:
    1,248
    Likes Received:
    41
    say no more #rumlife
     
  9. Chicken76

    Chicken76 Member

    Joined:
    10 Nov 2009
    Posts:
    864
    Likes Received:
    21
    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.
     
  10. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

    Joined:
    4 Dec 2007
    Posts:
    10,570
    Likes Received:
    792
    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.
     
    Last edited: 19 Mar 2018
  11. Chicken76

    Chicken76 Member

    Joined:
    10 Nov 2009
    Posts:
    864
    Likes Received:
    21
    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! :thumb:
     
  12. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

    Joined:
    4 Dec 2007
    Posts:
    10,570
    Likes Received:
    792
    ...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.
     
  13. Chicken76

    Chicken76 Member

    Joined:
    10 Nov 2009
    Posts:
    864
    Likes Received:
    21
    So probably the second in this list would fit, but not the third and fourth.
    https://www.robofun.ro/index.php?route=product/search&search=radiator pi
     
Tags: Add Tags

Share This Page