Here's someone's comparison between the B and B+ in terms of power: http://raspi.tv/2014/how-much-less-power-does-the-raspberry-pi-b-use-than-the-old-model-b
On Mon, May 11, 2015 at 10:25 PM, Joel Maslak <jmas...@antelope.net> wrote: > Rather then guessing on power consumption, I measured it. > > I took a Pi (Model B - but I suspect B+ and the new version is relatively > similar in power draw with the same peripherials), hooked it up to a lab > power supply, and took a current measurement. My pi has a Sandisk SD card > and a Sandisk USB stick plugged into it, so, if anything, it will be a bit > high in power draw. I then fired off a tight code loop and a ping -f from > another host towards it, to busy up the processor and the network/USB on > the Pi. I don't have a way of making the video do anything, so if you were > using that, your draw would be up. I also measured idle usage (sitting at > a command prompt). > > Power draw was 2.3W under load, 2.0W at idle. > > If it was my project, I'd build a backplane board with USB-to-ethernet and > ethernet switch chips, along with sockets for Pi compute modules (or > something similar). I'd want one power cable and one network cable per > backplane board if my requirements allowed it. Stick it all in a nice card > cage and you're done. > > As for performance per watt, I'd be surprised if this beat a modern video > processor for the right workload. > > > On Mon, May 11, 2015 at 5:16 PM, Rafael Possamai <raf...@gav.ufsc.br> > wrote: > > > Maybe I messed up the math in my head, my line of thought was one pi is > > estimated to use 1.2 watts, whereas the nuc is at around 65 watts. 10 > pi's > > = 12 watts. My comparison was 65watts/12watts = 5.4 times more power than > > 10 pi's put together. This is really a rough estimate because I got the > > NUC's power consumption from the AC/DC converter that comes with it, > which > > has a maximum output of 65 watts. I could be wrong (up to 5 times) and > > still the pi would use less power. > > > > Now that I think about it, the best way to simplify this is to calculate > > benchmark points per watt, so rasp pi is at around 406/1.2 which equals > > 338. The NUC, roughly estimated to be at 3857/65 which equals 60. Let's > be > > very skeptical and say that at maximum consumption the pi is using 5 > watts, > > then 406/5 is around 81. At this point the rasp pi still scores better. > > > > Only problem we are comparing ARM to x86 which isn't necessarily fair (i > am > > not an expert in computer architectures) > > > > > > > > > > > > On Mon, May 11, 2015 at 5:24 PM, Hugo Slabbert <h...@slabnet.com> wrote: > > > > > Did I miss anything? Just a quick comparison. > > >> > > > > > > If those numbers are accurate, then it leans towards the NUC rather > than > > > the Pi, no? > > > > > > Perf: 1x i5 NUC = 10x Pi > > > $$: 1x i5 NUC = 10x Pi > > > Power: 1x i5 NUC = 5x Pi > > > > > > So...if a single NUC gives you the performance of 10x Pis at the > capital > > > cost of 10x Pis but uses half the power of 10x Pis and only a single > > > Ethernet port, how does the Pi win? > > > > > > -- > > > Hugo > > > > > > > > > On Mon 2015-May-11 17:08:43 -0500, Rafael Possamai <raf...@gav.ufsc.br > > > > > wrote: > > > > > > Interesting! Knowing a pi costs approximately $35, then you need > > >> approximately $350 to get near an i5.. The smallest and cheapest > desktop > > >> you can get that would have similar power is the Intel NUC with an i5 > > that > > >> goes for approximately $350. Power consumption of a NUC is about 5x > that > > >> of > > >> the raspberry pi, but the number of ethernet ports required is 10x > less. > > >> Usually in a datacenter you care much more about power than switch > > ports, > > >> so in this case if the overhead of controlling 10x the number of nodes > > is > > >> worth it, I'd still consider the raspberry pi. Did I miss anything? > > Just a > > >> quick comparison. > > >> > > >> > > >> > > >> On Mon, May 11, 2015 at 4:40 PM, Michael Thomas <m...@mtcc.com> > wrote: > > >> > > >> As it turns out, I've been playing around benchmarking things lately > > >>> using > > >>> the tried and true > > >>> UnixBench suite and here are a few numbers that might put this in > some > > >>> perspective: > > >>> > > >>> 1) My new Rapsberry pi (4 cores, arm): 406 > > >>> 2) My home i5-like thing (asus 4 cores, 16gb's from last year): 3857 > > >>> 3) AWS c4.xlarge (4 cores, ~8gb's): 3666 > > >>> > > >>> So you'd need to, uh, wedge about 10 pi's to get one half way modern > > x86. > > >>> > > >>> Mike > > >>> > > >>> > > >>> On 5/11/15 1:37 PM, Clay Fiske wrote: > > >>> > > >>> On May 8, 2015, at 10:24 PM, char...@thefnf.org wrote: > > >>>> > > >>>>> > > >>>>> Pi dimensions: > > >>>>> > > >>>>> 3.37 l (5 front to back) > > >>>>> 2.21 w (6 wide) > > >>>>> 0.83 h > > >>>>> 25 per U (rounding down for Ethernet cable space etc) = 825 pi > > >>>>> > > >>>>> Cable management and heat would probably kill this before it ever > > >>>>> reached completion, but lol… > > >>>>> > > >>>>> > > >>>> This feels like it should be a Friday thread. :) > > >>>> > > >>>> If you’re really going for density: > > >>>> > > >>>> - At 0.83 inches high you could go 2x per U (depends on your > mounting > > >>>> system and how much space it burns) > > >>>> - I’d expect you could get at least 7 wide if not 8 with the right > > >>>> micro-USB power connector > > >>>> - In most datacenter racks I’ve seen you could get at least 8 deep > > even > > >>>> with cable breathing room > > >>>> > > >>>> So somewhere between 7x8x2 = 112 and 8x8x2 = 128 per U. And if you > get > > >>>> truly creative about how you stack them you could probably beat that > > >>>> without too much effort. > > >>>> > > >>>> This doesn’t solve for cooling, but I think even at these numbers > you > > >>>> could probably make it work with nice, tight cabling. > > >>>> > > >>>> > > >>>> -c > > >>>> > > >>>> > > >>>> > > >>>> > > >>> > > >
