The memory bus connects the memory system and the northbridge area of the chipset. This section of the chipset also connects directly to the central processing unit and the graphics system. While this means the northbridge is the center of many important computer functions, it is actually the computer’s memory that determines the bus’s speed. In essence, the speed of the computer’s memory creates the speed of this bus, which determines the speed of the rest of the system.
In computing, a bus transfers information from one location to another. Most modern computers have a large number of buses that cross-connect all sorts of different areas. The northbridge area of the chipset has four main buses. The front side bus connects to the central processing unit, the graphics bus connects to the graphic system, the internal bus connects to the southbridge section of the chipset, and the memory bus connects to the computer’s memory.
Each of these busses act independently of one another in most cases. The biggest exception to this is the memory and the front side busses. These control the most essential parts of the computer’s operations, and they are tied directly together. The speed of the computer’s memory dictates the speed at which information flows across the memory bus. This means that the processor is only able to send and receive information as quickly as the memory bus allows.
Using memory that is slower than the processor will have a direct impact on a computer’s speed. Basic calculations will often sit idle and occupy processor space while they wait for follow-up information. This can create periods of latency, even on a fast computer. Oddly, more strenuous operations are rarely affected by a slow memory bus, as the time it takes for the processor to compete its operations is often greater than the transferal time.
On a technical level, the memory bus is made of two parts. The data bus transfers information between the memory and the chipset. This portion of the bus is often incorrectly referred to as the memory bus, as it does the job most often associated with that part.
The second part of the memory bus is the address bus. The address bus tells the system where information may be stored as it comes into memory and where the information is when it needs to leave memory. The speed of the address bus affects every action on a computer, since all applications need some access to the memory. Regardless of how fast that information comes and goes from the system, it is limited by the speed at which the address bus directs it.