11 Replies Latest reply on Jan 29, 2014 8:47 AM by John Beetem

    RPi Model A or B?

    dnaman

      Last year I purchased what I thought was a Model-A Raspberry Pi from Element-14/Newark (US). Since I later had a project that needed a Model-B, I bought one of those also, a few weeks ago.

       

      Recently, I was checking out the differences between the two models and found that, according to various sources, The Model-B has 2 x USB ports (1 on the Model-A) and an Ethernet port (none on the Model-A) as well as a memory size difference.

       

      Now my "Model-A" has both an Ethernet port and two USB ports so I'm confused. Is it, in fact a Model-B (which I didn't think was around when I bought the first one)? Is my information on the model differences wrong? I would appreciate it if someone could shed some light on this and clear up my confusion.

       

      Also, what's the easiest way to check the amount of memory?

        • Re: RPi Model A or B?
          John Beetem

          You have a Model B.  RasPi Model B was the first to ship.  Originally RasPi was going to ship both, but there was so much demand for the Model B that they didn't bother with the Model A for a long time.

           

          The RasPi Hardware Wiki has a page with the RasPi hardware history, with a table that maps board revision numbers to amount of memory: http://elinux.org/RPi_HardwareHistory

          • Re: RPi Model A or B?
            merlin13

            There is indeed some confusion that was created because in some places the original Model B (with only 256 MB RAM) was named Model A. In fact, as far as I know the models are:

            - early Model B with 256 MB RAM, 2 USB, Ethernet - this one is incorrectly named Model A in some places

            - late/current Model B 512 MB RAM, 2 USB, Ethernet - more memory than early Model B but otherwise identical (well, there is also a small difference in GPIO pins)

            - Model A released last year, that indeed has only one USB, no Ethernet and only 256 MB of RAM.

             

            Hope this helps.

            1 of 1 people found this helpful
            • Re: RPi Model A or B?
              charlesb255

              Just to let you know, the way you tell the difference between the 256meg and the 512meg is that the 512meg has mounting holes

              and the 256meg does not.

                • Re: RPi Model A or B?
                  Roger Wolff

                  Not true...

                   

                  The "upgrade" to the PCB with the mounting holes came first. A few (thousand) of those were made with 256Mb RAM.

                   

                  Then the upgrade to 512Mb RAM was done. There was a small period with REV2 PCBS (with mouting holes) and only 256Mb RAM.

                   

                  But yes, chances are that with mounting holes has 512Mb RAM, and without has only 256.

                  • Re: RPi Model A or B?
                    John Beetem

                    Charles Burnaford wrote:

                     

                    Just to let you know, the way you tell the difference between the 256meg and the 512meg is that the 512meg has mounting holes and the 256meg does not.

                    This is true most of the time.  However, there were some Model B with rev 2.0 PC boards (with alignment holes) shipped with 256MB: see this thread chez RasPi: http://www.raspberrypi.org/phpBB3/viewtopic.php?f=63&t=48784

                     

                    Another way to tell your memory size is to look at the SDRAM chip, which is soldered on top of the SoC.  My original rev B has a Samsung K4P2G324ED.  The important part of the number is "2G32" which is 2Gi bit (256 MiB) by 32 bits wide.  A 512MiB Samsung SDRAM starts with "K4P4G32": 4Gi bit = 512 MiB.  I would expect Hynix memory numbers to be similar.  Memory chip manufacturers always quote sizes in bits, not bytes.  It's more impressive that way.