What are

What are 'Banks'?

Memory modules are arranged and addressed as 'banks'. Each bank is as wide as the data path, or bit width, of the module itself. To determine how many banks a particular module has, the sum of the data path's of each chip is divided by the module's data path. For example:

If a 32 bit module has 16 '4x4' DRAM chips, the sum of the data path's from the chips is 64. Divide 64 by 32 to arrive at 2. This would be a 2 bank module. So an 8MX32 using 4x4 chips is a 2 bank module, each bank is 4mx32.

Another example is a 36 bit module that has 8 '4x4' chips and 4 '4x1' chips. The sum of the data path's (4+4+4+4 + 4+4+4+4 + 1+1+1+1) is 36. Divide that total by the module data path, 36 / 36, and you get 1. This makes a single bank 4mx36.

Note that SDRAM chips themselves have their own internal bank arrangements.

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