Explaining Chipsets, the Defining Piece of Your Motherboard - The North Bridge
(Page 2 of 4 )
The north bridge chip is also called the Memory Controller Hub (MCH), for reasons that will become obvious. It connects directly to the CPU and communicates with RAM, the video card, and the south bridge. It usually contains the memory controller, but not always. With socket 754, socket 939, and socket 940 CPUs, the memory controller is located in the CPU itself. These include CPUs from AMD such as the Athlon 64.
As you might guess, the north bridge has a critical effect on your computer’s performance, especially for memory- or graphics-intensive operations – unless of course you’re using one of the kinds of CPUs mentioned above. This is one situation in which an apparently small thing can have a big effect: if you have two chipsets, but one of them has a north bridge with a better memory controller, then (everything else being equal) the system with that chipset will show a better performance. That improvement will be not just for one function, but overall performance for the whole system.
It follows that the north bridge dictates the types and maximum amount of memory you can have in your system (except for systems with the Athlon 64 CPU, which, as I've already mentioned, has the memory controller in the CPU itself rather than in the north bridge). When you buy a motherboard, since you are pretty much stuck with whatever chipset you choose, you need to consider this factor, since it can limit your possibilities for expanding your system in some very important ways.
Connections are very important too, of course. To connect to the graphics card, the north bridge uses a PCI Express bus. Currently, on the GMCH chip for Intel’s top-of-the-line chipsets for performance desktops, this bus functions at a speed of 8 GB/s. The memory bus, which connects the chipset to RAM, is even faster. (This is for the 955X Express chipset).
The connection to the CPU is often called the local bus. In the case of the Intel chipset mentioned above, it is slightly faster than the connection between the chipset and the graphics card. The CPU-chipset connection is slower than the chipset’s connection to the RAM, however.
Next: The South Bridge >>
More Motherboards Articles
More By Terri Wells
