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 As noted in the introduction, there''s a virtual alphabet soup of memory types: SDRAM, EDO, FPM, SIMM, and DIMM. sdramdimm It certainly can create a great deal of confusion. RAM itself stands for "random access memory," meaning the CPU can access any memory address without reading all addresses before it. (ROM—read only memory—is random access, too, but you can''t write to it). It gets worse, because memory comes in different speeds, and some types don''t work in some systems. Here''s the rundown on the three memory types used in today''s systems.... SDRAM. Synchronous DRAM SDRAM''s speed is typically measured in MHz (for example, sdramdimm 100MHz), although you do see references to 10ns SDRAM ("ns" stands for nanosecond or one billionth of a second). SDRAM for PCs comes in DIMMs. These refer to SDRAM DIMMs rated at different memory bus speeds. For any CPU running at a 100MHz bus speed you should get SDRAM. Some future motherboards will support SDRAM. Although there''s a price premium, SDRAM will run in a PC100 system. What is SDRAM? SDRAM is an acronym for Synchronous Dynamic Random Access Memory. The term "Synchronous" means that the clock cycle of the memory is exactly synchronized with the clock cycle of the bus. Every calculation and operation a PC performs is timed according to a clock ticking millions of times each second, its clock cycle or megahertz rating. If the memory clock cycle is not in sync with the bus clock cycle, system problems will occur. What is Cache Memory? Cache, pronounced "cash", is a high-speed memory designed to supply the processor with the most frequently requested data and instructions. The information located in the cache memory can be accessed sdramdimm many times faster than information in the system''s main memory. The more information your system can retrieve sdramdimm from the cache memory, the more efficient the system will run. Level 1 (L1) cache, also referred to as Primary Cache, is normally located inside the CPU chip. Level 2 (L2) sdramdimm cache, also referred to as Secondary Cache, was normally located on the system board near the CPU in the past. In today''s systems, both are physically located within the CPU and as a result are not upgradable. You sdramdimm can think of RAM as an incredibly fast hard drive that stores information temporarily instead of permanently. When you start a program it is loaded from the hard drive into RAM. When a program is running in RAM it can run hundreds to thousands of times faster than it can if run directly from the hard drive. The problem is that the capacity of a standard hard drive is many times the size of a computer''s RAM size, meaning it is possible to load so many programs that the RAM can no longer hold them. When that happens, your computer''s virtual memory kicks in, and that''s bad. Virtual memory is simply your hard drive trying to act like a RAM chip. Since the hard drive is so much slower than real memory, programs stutter and sometimes crash when the hard drive has to do a job it was never designed for. There are only two sdramdimm solutions to this problem: close some programs until virtual memory is no longer needed, or add more physical memory. If you can afford it (and current memory prices are low enough that practically anyone should be able to), the sdramdimm latter solution is always preferable. Would you like to find ddr, simm or dimm memory but aren't sure where to look? Search no further. We have any type of memory for any computer you have. Shop our pages and purchase everything you need online!
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