INTL 3:770/1 3:770/3   
   REPLYADDR tnp@invalid.invalid   
   REPLYTO 3:770/3.0 UUCP   
   MSGID:  7ba5b994   
   REPLY:  2cc22041   
   PID: SoupGate-Win32 v1.05   
   On 16/04/2024 17:36, Pancho wrote:   
   > On 16/04/2024 10:59, Theo wrote:   
   >> The Natural Philosopher  wrote:   
   >>>> The Pi 4B will definitely throttle with only a ventilated case if it is   
   >>>> anything other than sitting idle all the time.   
   >>>>   
   >>> I am not interested in proof by assertion   
   >>> I had mine up to 130% on 'top' and it never made more than 76°C   
   >>   
   >> You do know that 'top' won't show throttling?  Throttling means the   
   >> CPU is   
   >> clocked lower than the maximum frequency to reduce heat generation - top   
   >> will still show '100%' of CPU (for one core) but that will be 100% of a   
   >> lower clock speed.   
   >>   
   >> cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq   
   >>   
   >> shows you the current clock of CPU core 0 and:   
   >>   
   >> sudo vcgencmd get_throttled   
   >>   
   >> will tell you the throttling status:   
   >>   
   >>   
   >> #### get_throttled   
   >>   
   >> Returns the throttled state of the system. This is a bit pattern.   
   >>   
   >> | Bit | Meaning |   
   >> |:---:|---------|   
   >> | 0 | Under-voltage detected |   
   >> | 1 | Arm frequency capped |   
   >> | 2 | Currently throttled |   
   >> | 3 | Soft temperature limit active |   
   >> | 16 | Under-voltage has occurred |   
   >> | 17 | Arm frequency capped has occurred |   
   >> | 18 | Throttling has occurred |   
   >> | 19 | Soft temperature limit has occurred   
   >>   
   >>   
   >> For example if I run 'stress -c 4' then get_throttled gives me:   
   >> throttled=0xe0008   
   >>   
   >> so the temperature limit is in operation and throttling has occurred   
   >> in the   
   >> past.  (this Pi4 has cooling, I can't remember but I think there's a   
   >> heatsink and fan in there)   
   >>   
   >> $ sudo vcgencmd measure_temp   
   >> temp=84.7'C   
   >>   
   >> so it's up near its thermal limit.   
   >>   
   >>>> I don't see the point of letting it throttling when an inexpensive fan   
   >>>> will keep it at full speed under any load.   
   >>>>   
   >>> I question that it will in fact throttle.   
   >>>   
   >>> Like so much 'everybody knows'  when you look at it it is in fact   
   >>> 'everyone believes because people selling fans told them so.   
   >>   
   >> 'Everybody knows' because they have evidence, not assertions.   
   >>   
   >>> The whole point of ARM is its lower power and lack of need for forced   
   >>> cooling   
   >>   
   >> Everyone's been thermally limited for maybe 15 years, it's just that Arm   
   >> cores have traditionally targeted a lower thermal envelope in devices   
   >> where   
   >> forced air cooling isn't an option.  The way this works is that CPUs work   
   >> until they hit their thermal envelope and then throttle.  No popular   
   >> application processor for maybe a couple of decades has been able to   
   >> power   
   >> all the silicon at once to max performance and stay within the thermal   
   >> budget.   
   >>   
   >   
   > I think this thread is lacking precise, clear language, and people are   
   > making false comparisons. Talking about ventilated cases is confusing, I   
   > don't know what a thermal budget is.   
   >   
   > There are four  points:   
   >   
   > 1) Passive cases, where the case is a heat sink,  are enough to keep a   
   > rPi4 below throttle temperatures, under any load, assuming ambient less   
   > than 35C.   
   >   
   > 2) With no heatsink at all the rPi4 will throttle under compute   
   > intensive workloads.   
   >   
   > 3) The rPi4 can perform useful day-to-day tasks without any heatsync,   
   > passive or forced, without throttling. I ran Motioneye, cctv, on mine   
   > for a couple of years before buying a case.   
   >   
   > 4) Most of us don't use the rPi4 for continuous compute intensive tasks.   
   >   
   > There, that should make everyone happy :-)   
   >   
   >   
      
   Mine runs hot because there is a TV hat bolted on top. And a SSD drive   
   bolted underneath   
      
   that pushes up the case internals way more than the Pi does   
   But it is still happy and unthrottled   
      
   --   
   "Corbyn talks about equality, justice, opportunity, health care, peace,   
   community, compassion, investment, security, housing...."   
   "What kind of person is not interested in those things?"   
      
   "Jeremy Corbyn?"   
      
   --- SoupGate-Win32 v1.05   
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)   
   SEEN-BY: 10/0 1 15/0 90/1 103/705 105/81 106/201 128/260 129/305 135/220   
   SEEN-BY: 135/225 153/757 7715 218/0 1 601 700 840 870 930 220/70 221/1   
   SEEN-BY: 221/6 360 226/17 30 100 227/114 229/110 111 112 113 200 206   
   SEEN-BY: 229/307 317 400 426 428 470 550 616 664 700 240/1120 266/512   
   SEEN-BY: 267/800 282/1038 291/111 292/854 301/1 113 812 310/31 320/219   
   SEEN-BY: 322/757 335/364 341/66 342/200 396/45 460/58 633/280 712/848   
   SEEN-BY: 770/1 3 100 330 340 772/210 220 230 5020/400 1042 5058/104   
   SEEN-BY: 5075/35   
   PATH: 770/3 1 218/840 221/6 301/1 218/700 229/426