3 Replies Latest reply on Oct 3, 2011 11:00 PM by Victor43

    How does the Southbridge Chipset Work


      I have a question about the older Southbridge chipsets. You see I own several motherboards that support older CPU's and wanted to find out how the "hub" that the Southbridge controls really works. My interest is focussed on the how data travels between the Southbridge and the Northbridge chipsets. My understanding is that when data is being retrieved from IDE device i.e IDE Hard Drive like for example when Windows is being loaded on start up of the computer. While that is happening I can see data being transfered from the IDE device via the Southbridge chip and then to the Northbridge chip and from there to the CPU and to Memory. Of course I understand there is data sent to the AGP (video card) via theNorthbridge and then CPU and to Memory and then the AGP video card is notified of pending data which updates the monitor/display. Now my question is really when data is being retrieved from the IDE device as described just above, does the data get sent to other devices like to the USB ports or Ps/2 devices or to the PCI bus ? I can understand that during the early stages of the Windows bootup sequence data is sent to all devices on the motherboard to check for the presence of these devices so that Windows can load appropriate drivers and perhaps even initialize these devices on bootup. But lets say following bootup and after the detection of these devices takes place does data get randomly sent to all other devices just like in the case of how a network hub works. The old network hubs would forward  packets to all ports located on the device like a repeater. Does the Southbridge chipset do the same in that data is repeated to all devices on the Southbridge hub ? I don't believe that it does repeat data to all devices located on the Southbridge hub because it would cause collisions and perhaps data loss and lowering system performance. But I would like to know the answer if my theory is correct or not. I do understand that when a device has something to say like data to send it notifies the Interrupt controller and then waits for its turn to send the data to the appropriate chipset....I may be not quite accurate of how data travels on the motherboard so please accpet my apologies for being inaccurate or mistaken. But I hiope my question is clear and if not I would be happy to explain myself better.


      Thanks in advance



        • 1. Re: How does the Southbridge Chipset Work



          I suggest you to check for related information over the Internet.


          I believe that there might be some online courses for computer architectures that may help too.

          1 of 1 people found this helpful
          • 2. Re: How does the Southbridge Chipset Work

            I love deep questions:


            The southbridge acts like a post office.

            It only sends data to specific addresses on it down stream bus or forward requests upstream to the processors.

            Some devices are smart enough that they do not need to work via the processors and can via the chipset transfer data directly between each other (peer to peer)


            Some commands are broad cast commands which are used to during start-up to see and report to the processor what devices are connected.


            Old networking hubs were broadcast devices and sent to every one. newer switches and routers direct the data to the intended target.

            1 of 1 people found this helpful
            • 3. Re: How does the Southbridge Chipset Work

              Thanks very much for the helpful replies to both of you. I was wondering if anyone around these forums might know of these rogue chips that are used on motherboard as a command and control per say in order to take control of the computer. Does anyone know any more then what the article is talking about ?


              Here is the link to the article...... http://www.rumormillnews.com/cgi-bin/archive.cgi?read=114722


              Best Regards