Considering getting a boost from your CPU, RAM or GPU through overclocking? Before you begin tinkering with the hardware on your motherboard, make sure you understand the following terms and concepts about overclocking:
FrontSide Bus (FSB)
The frontside bus, or FSB, is the data bus that sends information from the processor to the rest of the system, including the main memory. As the middleman between your CPU and the rest of the system, the FSB plays a vital role in overclocking. In fact, the speed rating you’ll see on PC specs refers to the CPU’s multiplier times the FSB’s speed. As such, increasing the clock speed of the FSB is the most common way to overclock a computer.
Some CPUs do not have FSBs. For example, the AMD Athlon 64 processor has a built-in memory controller, rather than a separate FSB on the motherboard’s core logic chipset. This can still be altered in much the same way a FSB’s clock speed is changed. More recently, Intel’s X58 Chipset and Core i7 processors began incorporating a Quick Path Interconnect (QPI), also known as a baseblock. These processors will be more complicated to overclock.
As mentioned above, the CPU has an internal multiplier that is set by the manufacturer. This multiplier is multiplied to the FSB speed to get the system’s overall speed. For example, if your CPU had a 16x multiplier and an FSB speed of 100MHz, your overall processor speed would be expressed as 1.5 GHz. In theory, you could overclock a CPU by changing this multiplier. However, most CPUs are “multiplier locked,” meaning that the internal multiplier cannot be altered.
Most systems with Intel or AMD processors allow you to set a memory divider. The memory divider lets you slow down the RAM speed relative to the FSB. This is useful if you are using memory that does not support overclocking. The memory divider is expressed as a ratio, and the default is usually 1:1. With a 1:1 memory divider, any increase in the FSB speed will be passed on to the RAM. While namebrand RAM usually supports higher speeds, generic RAM may malfunction if it’s pushed beyond its rated speed. For situations like these, you can alter your memory divider—say to 5:4—so that the RAM remains at the same speed before it was overclocked, while your FSB operates at the overclocked speed. This will give you less of a performance enhancement than maintaining a 1:1 memory divider, but if your RAM doesn’t support faster speeds, it’s a necessary tradeoff.
The stock speed is the default speed setting for your computer for all hardware. This is usually equal to the clock speed on your CPU. If a hardware component has a higher max speed than the stock speed of your system, it’ll automatically be throttled down. For example, if you install a 200 MHz RAM module into a 166 MHz system, the RAM will automatically operate at 166 MHz.
Core Voltage, Chipset Voltage and Memory Voltage
When components are overclocked, the often require more electricity in order to remain stable. Each of these components has a separate voltage that is controlled by the system. If your system becomes unstable after overclocking, you may need to slightly increase the voltage by about 0.05V to 0.1V. Note that adding voltage won’t directly improve performance (like giving a car more gas). Increased voltage will increase the amount of heat thrown by the component, which may cause damage if a certain threshold is passed.
These terms will help you understand some of the tutorials and concepts about overclocking that you’ll find here on R-TT.com. Bookmark this page and return to it in case your encounter an unfamiliar term during your research.