Intel Hub Architecture

Intel Hub Architecture

Intel recently modified the very popular Northbridge/Southbridge chipset in order to make an overall faster and more efficient motherboard. The GMCH (Graphics and Memory Controller Hub) is the Northbridge equivalent in Intel's new IHA or (Intel Hub Architecture). The ICH (I/O Controller Hub) is the equivalent of the Southbridge. They are essentially the same thing with some significant improvements. Basically the rate at which buses on your mainboard could transfer data is becoming a huge bottleneck for overall system performance. Because of this, both AMD and Intel are designing new ways to manage their chipsets. AMD is using HyperTransport and an on-die PCI controller, but that is a different write up.

Here is the old Northbridge/Southbridge setup. Note that the southbridge communicates through the PCI bus, thereby competing with everything on the PCI bus for time. This makes it slow if you are trying to read your hard drive (IDE) and download a webpage (PCI) at the same time.

Typical CPU Chipset
    +-----------+
    |           |
    | Processor |
    |           | 
    +----+------+
         |  
         |Front Side Bus
         | 
         |
    +----+------+         
    | North     |---- Memory  
    |  Bridge   |---- AGP        
    |           |---+-- PCI 
    |           |   |
    +-----------+   |
                    |PCI BUS
                    |  
             +------+----+
             | South     |---- Audio
             |  Bridge   |---- ISA
             |           |---- IDE
             |           |---- USB
             +-----------+

Now here is the IHA chipset from Intel. This clears up a lot of traffic by putting the PCI controller on the ICH/Southbridge and creating a faster and optimized bus between the GMCH and ICH. The new bus runs at almost twice the speed of the PCI bus (233Mhz) and is able to optimize the data flow depending on the type of data being sent/received.

Intel's New Chipset
    +-----------+
    |           |
    | Processor |
    |           | 
    +----+------+
         |  
         |Front Side Bus!
         | 
         |
    +----+------+         
    |           |---- Memory  
    |   GMCH    |---- AGP        
    |           | 
    |           |   
    +-----+-----+   
          |
          |A New
          |233Mhz Bus
          |  
    +-----+-----+
    |           |---- Audio
    |    ICH    |---- ISA
    |           |---- IDE
    |           |---- USB
    |           |---- PCI*
    +-----------+

This has been implemented on Intel motherboards since the 815 chipset. So you might be using it in your computer right now! Their new bus can, as mentioned above, optimize data flows. The bus controller will recognize the difference between streaming data and hard drive accesses and allow more or less freedom and access time depending on the type of data. This setup also allows the GMCH to focus on graphics and memory access, probably the two most important functions of a chipset. The less important activities are moved down into the ICH.

This improvment helps when you are using a high load, or many multimedia type devices at the same time. It won't help your processor render a large AutoCAD graphic, but it will help in bus intensive activities like mp3 playing, video watching, and internet browsing.