tailieunhanh - CompTIA A+ Complete Study Guide phần 2

Như đã đề cập trong "khe cắm bộ nhớ và cache ngoài" trước đó trong chương này, bộ nhớ cache là một chip nhớ rất nhanh được sử dụng để giữ các dữ liệu và hướng dẫn có nhiều khả năng được yêu cầu bởi CPU. Các bộ nhớ cache nằm trên CPU là được biết đến như là bộ nhớ cache được ghi lại và thông tin được | 30 Chapter 1 Identifying Personal Computer Components to run that fast you must make special arrangements to ensure that an overclocked CPU does not destroy itself from the increased heat levels. An advanced cooling mechanism such as liquid cooling might be necessary to avoid losing the processor and other components. Cache As mentioned in the Memory Slots and External Cache section earlier in this chapter cache is a very fast chip memory that is used to hold data and instructions that are most likely to be requested next by the CPU. The cache located on the CPU is known as L1 cache and is generally smaller in comparison to L2 cache which is located on the motherboard. When the CPU requires outside information it believes it requests that information from RAM. The cache controller however intercepts the request and consults its tag RAM to discover if the requested information is already cached either at L1 or L2. If not a cache miss is recorded and the information is brought back from the much slower RAM but this new information sticks to the L1 and L2 cache on its way to the CPU from RAM. Voltage Regulator Module The voltage regulator module VRM is the circuitry that sends a standard voltage level to the portion of the processor that is able to send a signal back to the VRM concerning the voltage level the CPU needs. After receiving the signal the VRM truly regulates the voltage to steadily provide the requested voltage. Speed The speed of the processor is generally described in clock frequency MHz or GHz . There can be a discrepancy between the advertised frequency and the frequency the CPU uses to latch data and instructions through the pipeline. This disagreement between the numbers comes from the fact that the CPU is capable of splitting the clock signal it receives from the oscillator into multiple regular signals for its own use. 32- and 64-Bit System Bus The set of data lines between the CPU and the primary memory of the system can be 32 or 64 bits wide .