The Raspberry Pi 3 Model B Q&A thread

[jdb]

Due to the higher clockspeeds, Pi 3 will run hotter than Pi 2. The oft-repeated line that "Raspberry Pi doesn't need a heatsink" is now "you will need a heatsink if you run into thermal throttling".

The existing 2A Pi power supply will be sufficient for the vast majority of users. The 2.5A option is there for people wanting to use high-current USB peripherals (or e.g. a Pi 3 and a DSI display).

[poing]

OK, Thanks gregeric.

I know for a fact that the popular Edimax ..n WiFi dongle couldn't handle an access point on the Pi 1 and 2, not sure if it was hardware or driver limited. So I had to buy one with the Realtek chip. Obviously I'm trying to find out if both hardware and software allow the Pi3 to be used as an access point. Guess I have to wait until someone knowledgeable tries it.

[Zincat]

I also noted the Users Manual states "This product shall only be connected to an external power supply rated at 5V dc, and a maximum current of 1500 – 2000 mA".

Elsewhere I have seen mention of 2.5A supply. Can someone clarify the power requirements / limits. Is the micro USB power connector even rated for 2.5A ?

I must ask this as well. I am using a 3A supply. Will the Pi3 still be able to power an external 2.5 inch HDD even though its own power requirements rose?


Not really sure if I'll buy it though. Really disappointed by the lack of Gigabit ethernet. I use the pi as FTP server / file server/ multimedia center. And the lack of Gigabit ethernet is starting to be quite bad...

[GTR2Fan]

In the Users Manual submitted to the FCC it says "This product should not be overclocked as this may make certain components very hot. This product should be operated in a well ventilated environment and should not be covered".

I believe the leaflet in the box my Pi2B arrived in said exactly the same thing. It's very good advice for those who don't understand overclocking, and that seems to be almost everybody.

[Massi]

Pimoroni say "We've redesigned our Pibow case to provide more venting, a place for installing a heatsink if you really want to push your Pi". In the Users Manual submitted to the FCC it says "This product should not be overclocked as this may make certain components very hot. This product should be operated in a well ventilated environment and should not be covered".

Are there any details on what temperatures should be expected from a Pi 3 and the best way to deal with any thermal issues there may be ?

I also noted the Users Manual states "This product shall only be connected to an external power supply rated at 5V dc, and a maximum current of 1500 – 2000 mA".

Elsewhere I have seen mention of 2.5A supply. Can someone clarify the power requirements / limits. Is the micro USB power connector even rated for 2.5A ?

in the first page of this same topic there's a link to a pimoroni first review, that also reports temperatures

[RaTTuS]

http://blog.pimoroni.com/raspberry-pi-3/

[jamesh]

I also noted the Users Manual states "This product shall only be connected to an external power supply rated at 5V dc, and a maximum current of 1500 – 2000 mA".

Elsewhere I have seen mention of 2.5A supply. Can someone clarify the power requirements / limits. Is the micro USB power connector even rated for 2.5A ?

I must ask this as well. I am using a 3A supply. Will the Pi3 still be able to power an external 2.5 inch HDD even though its own power requirements rose?


Not really sure if I'll buy it though. Really disappointed by the lack of Gigabit ethernet. I use the pi as FTP server / file server/ multimedia center. And the lack of Gigabit ethernet is starting to be quite bad...

Why? I have an entirely 100baseT network at home, plus some wireless that deals with at least 3 tablets and two PC's and a couple of TV's, all streaming at the same time.

If you really need more bandwidth for any one of those particular use cases you quote, just buy another Pi to take spread the load.

AFAIK, you will be able to use the HDD you mention.

[hippy]

Not really sure if I'll buy it though. Really disappointed by the lack of Gigabit ethernet. I use the pi as FTP server / file server/ multimedia center. And the lack of Gigabit ethernet is starting to be quite bad...

I personally don't see the need for Gigabit Ethernet, eSATA or USB 3.0 and wouldn't consider lack of those a serious failing in a £30 computer, and same too for only 1GB of RAM and no 5GHz Wi-Fi.

I would agree they would all be nice to have, though not essential for most use cases, and one rarely gets everything one wants at the desired price. There have to be compromises and I think the Foundation's focus on keeping costs low is the right call.

[dom]

I would expect it to be about 50% better simply through raw CPU performance. I'm not sure how much faster NEON is on the A53 though, that might give even more performance.

In addition to the 50% CPU performance, the NEON is twice as wide, so performance may be up to 3 times as high.
As an example we can now play Blu-Ray quality MPEG-2 with software decode.

HEVC performance benefits too.

[0xFF]

I would expect it to be about 50% better simply through raw CPU performance. I'm not sure how much faster NEON is on the A53 though, that might give even more performance.

In addition to the 50% CPU performance, the NEON is twice as wide, so performance may be up to 3 times as high.
As an example we can now play Blu-Ray quality MPEG-2 with software decode.

HEVC performance benefits too.

Nice.
Recently I bought a mpeg2 codec licence for RPI2, just to watch one mpeg2 movie.
I hope It will run smoothly with RPI3 software codec.

[jamesh]

I would expect it to be about 50% better simply through raw CPU performance. I'm not sure how much faster NEON is on the A53 though, that might give even more performance.

In addition to the 50% CPU performance, the NEON is twice as wide, so performance may be up to 3 times as high.
As an example we can now play Blu-Ray quality MPEG-2 with software decode.

HEVC performance benefits too.

Do you need any specific compile flags to get that extra NEON performance? I'll try a build of x264 to see what sort of encode speed I can get.

[gregeric]

I'm very interested in what the GPIOs are used for.
Is there a chance we get a list to see what has changed regarding B+ B2 ?
Especially for the BT/WIFI

Full Pi 3 pin-mapping can be seen in bcm2710-rpi-3-b.dts over here: https://github.com/raspberrypi/linux/co ... 3bd3fa48b7

[Zincat]

Why? I have an entirely 100baseT network at home, plus some wireless that deals with at least 3 tablets and two PC's and a couple of TV's, all streaming at the same time.

If you really need more bandwidth for any one of those particular use cases you quote, just buy another Pi to take spread the load.

AFAIK, you will be able to use the HDD you mention.

Thank you for the answer about the hard disk.

About the fast ethernet, I understand that my usage of the pi is not a standard case. But I don't just stream, I often transfer multiple-GB files over the home network, either towards the pi-connected hd or from it to other pcs. And the increased speed a gigabit ethernet would offer would be much welcome. Plus I also use it as an ftp server and my internet connection is faster than 100 Mbit. So the fast ethernet on the pi3 ends up being a bottleneck... My pi2 is basically an always on, internet connected small server.

So yes, I understand that this is probalby not a priority for the raspberry foundation, but I would have loved to see a Gigabit ethernet on the pi3.

[fruitoftheloom]

Why? I have an entirely 100baseT network at home, plus some wireless that deals with at least 3 tablets and two PC's and a couple of TV's, all streaming at the same time.

If you really need more bandwidth for any one of those particular use cases you quote, just buy another Pi to take spread the load.

AFAIK, you will be able to use the HDD you mention.

Thank you for the answer about the hard disk.

About the fast ethernet, I understand that my usage of the pi is not a standard case. But I don't just stream, I often transfer multiple-GB files over the home network, either towards the pi-connected hd or from it to other pcs. And the increased speed a gigabit ethernet would offer would be much welcome. Plus I also use it as an ftp server and my internet connection is faster than 100 Mbit. So the fast ethernet on the pi3 ends up being a bottleneck... My pi2 is basically an always on, internet connected small server.

So yes, I understand that this is probalby not a priority for the raspberry foundation, but I would have loved to see a Gigabit ethernet on the pi3.

As stated ad-infinitum the SoC only has one USB BUS, therefore changing the SoC is the only Option which would costalottadosh, 2 years development meaning more staff and flush 4 years of work down the toilet, the best you can achieve is using a USB 3 Ethernet Adaptor:

http://www.jeffgeerling.com/blogs/jeff- ... networking

""USB Gigabit LAN (10/100/1000): 222 Mbits/sec (27.8 MB/sec)""

[Massi]

the best you can achieve is using a USB 3 Ethernet Adaptor:

http://www.jeffgeerling.com/blogs/jeff- ... networking

""USB Gigabit LAN (10/100/1000): 222 Mbits/sec (27.8 MB/sec)""

and in any case you'll have to share this bandwidth with other usb attached devices (like your hdd..)

[scotty101]

Is there any information about what the Bluetooth device is capable of?
Bluetooth Internet Tethering? Audio output to speakers? Audio input from smartphones?

[RaTTuS]

from https://www.raspberrypi.org/magpi/pi-3-interview/
USB and PXE network boot
Even with the chip designed and taped out in March of last year, the Foundation had some final input for Broadcom in order to add twonew features: direct USB massstorage and PXE network boot capabilities. “Gordon rewrote the boot ROM for the chip and then provided an updated boot ROM to Broadcom, saying ‘shove this in the chip, it’ll work’,” Eben laughs. “And it does!

OOh -0 ooh ohh no SD card neded ?

[dom]

Do you need any specific compile flags to get that extra NEON performance? I'll try a build of x264 to see what sort of encode speed I can get.

No, NEON instructions are just quicker. No compiler flags need changing.

[gregeric]

jdb answered that directly after my question - it`s mcs7 20MHz for 72.2Mbps link speed.

[karrika]

I would expect it to be about 50% better simply through raw CPU performance. I'm not sure how much faster NEON is on the A53 though, that might give even more performance.

In addition to the 50% CPU performance, the NEON is twice as wide, so performance may be up to 3 times as high.
As an example we can now play Blu-Ray quality MPEG-2 with software decode.

HEVC performance benefits too.

This sounds really great. The Pi 2 was already good enough for beaming out video using omxplayer. Having higher quality wood be a good plus for theater lighting. Many backgrounds are actually video clips.

[bitbank]

1g of ram, 64bit cpu, what is point? more ram eating?

ARMv8 brings a bunch of improvements including double the number of general purpose registers, double-wide registers, double the number of NEON registers, and an improved instruction set (including integer divide). The extra registers alone usually make C/C++ code execute faster.

[daniel.nonlinear]

Hi.
Is the I2S bus still available on the Pi3?

Thanks,
Daniel

[mikerr]

Any improvements in power management - i.e. is there a sleep mode < 50ma ?
(this has always been a drawback of pi for battery based apps)

[fanoush]

1g of ram, 64bit cpu, what is point? more ram eating?

ARMv8 brings a bunch of improvements including double the number of general purpose registers, double-wide registers, double the number of NEON registers, and an improved instruction set (including integer divide). The extra registers alone usually make C/C++ code execute faster.

There is also the ILP32 mode
http://infocenter.arm.com/help/index.js ... 01s01.html
however it does not seem to be used so far and support is weak
https://wiki.linaro.org/Platform/arm64-ilp32
In such mode most arithmetic is 32 bit unless you use 64bit type explicitly, i.e. in c++ 'long' type is still 32bit but 'long long' is 64bit and uses native 64bit registers. This is similar to https://en.wikipedia.org/wiki/X32_ABI (which didn't get much popularity).

[lb]

1g of ram, 64bit cpu, what is point? more ram eating?

ARMv8 brings a bunch of improvements including double the number of general purpose registers, double-wide registers, double the number of NEON registers, and an improved instruction set (including integer divide). The extra registers alone usually make C/C++ code execute faster.

There is also the ILP32 mode
http://infocenter.arm.com/help/index.js ... 01s01.html
however it does not seem to be used so far and support is weak
https://wiki.linaro.org/Platform/arm64-ilp32
In such mode most arithmetic is 32 bit unless you use 64bit type explicitly, i.e. in c++ 'long' type is still 32bit but 'long long' is 64bit and uses native 64bit registers. This is similar to https://en.wikipedia.org/wiki/X32_ABI (which didn't get much popularity).

Hmm, interesting. However, the article itself notes that the advantages compared to AArch32 are quite slim. Probably not worth the effort to implement something very special like that? The only motivation for the ABI seems to be that it makes it easy to port badly written software... really very weak justification.