Categories: PCs and Hardware Glossaries Solutions: Printer Memory Versus System Memory Memory's Too Fast? L2 Cache Specifications How Computers Use Memory More Hardware Solutions

Until the advent of EDO RAM (see below), all main memory found in PCs was of the fast page-mode variety. That's why the name wasn't well known: There was no need to state the type, since there was only one. The access times of FPM RAM dropped as the technology matured, from 120 ns (nanoseconds) down to the now-common access time of 60 ns. The Pentium processor, however, allows for a bus speed of 66 MHz, which is faster than FPM RAM can keep up with. The speed of a 60-ns RAM module performing random page access (where page refers to a region of address space) is below 30 MHz--far slower than the bus speed. So DRAM makers came up with the concept of the RAM cache.

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Published as Tutor in the 10/21/97 issue of PC Magazine.