All memory must be added in “banks.” In systems that use single-channel memory access, a bank of memory is the amount of memory (in bits) equal to the data bus of the CPU. Therefore, a bank isn't a fixed amount of memory but varies with the data bus of the CPU. In other words, for a CPU with a 64-bit data bus (Pentium, PII, PIII, Celeron, K6, Athlon, and so on), a bank of memory is the total of one or more identical modules (same type, size, speed, and so on) that add up to 64 bits in width. Refer back to Figure 7.3 to see how different processors and module combinations work together to provide a bank of memory.
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