PC Hardware in a Nutshell, Second Edition

Installing Memory

Installing a SIMM or DIMM module is straightforward. Most recent motherboards automatically detect installed memory modules regardless of the slot they occupy, but it is good practice to fill banks from the lowest numbered to the highest. For example, if the motherboard has three banks, fill Bank 1 only after Bank 0 is filled, and fill Bank 2 only after Banks 0 and 1 are filled.

Some motherboards require that larger modules be installed in lower numbered banks. For example, if the motherboard has three DIMM sockets, Bank 0 is currently occupied by a 32 MB DIMM, and you are installing two 64 MB DIMMs rather than simply installing the two new 64 MB DIMMs in Banks 1 and 2, you may need to remove the 32 MB DIMM from Bank 0, install the 64 MB DIMMs in Banks 0 and 1, and then reinstall the original 32 MB DIMM in Bank 2.

That rule is not invariable, though. A few motherboards require that smaller modules be installed in the lower banks. Some motherboards don’t care which module you install in which bank. Best practice is to check the manual before installing memory. If no documentation is available, experiment by moving modules around. If some or all of the memory is not recognized during the boot-time memory check or in CMOS Setup, try rearranging the modules. If all memory is recognized, you can safely assume that you have the modules installed correctly.

Tip

Windows and recent Linux releases automatically recognize the full amount of memory physically installed. However, ...