Memory Specifications for Home Computers

Memory

If you're running Windows 95 or Windows 98, I recommend that you have a minimum of 32MB of RAM, preferably 64MB. For Windows NT, you need a minimum of 64MB, preferably 128MB, and consider more. Make sure you get memory that matches your motherboard and CPU speed. Also you need to take into account the "bank" features of the motherboard. Many motherboards require that you completely fill a bank, which may be a combination of two or four memory chips. For instance if there are 4 memory slots on the motherboard, and you want 32MB of memory, that doesn't necessarily mean that you can get one 32MB memory chip and it will work. If the memory slots are in banks of two, then you would need 2 - 16 MB chips instead of 1 - 32MB chip. You can't mix and match within a bank. The chips within a bank need to be identical. For example if you have 2 banks of 2, you could use 2 - 16 MB chips in one bank and 2 - 8MB chips in the other bank, but you can't put 1 - 16MB chip and 1 - 8MB chip within the same bank. You also need to consider future expansion capabilities. Using this same 32MB example, you could get 4 - 8MB chips, but this would fill all of your memory slots, so that later if you wanted to add more memory, you'd need to replace chips, whereas if you got 2 - 16MB chips, then you still have 2 slots left for expansion. Be specific if you tell the computer store to install the memory chips for you, because most will fill all of the slots, because it's cheaper for them, and later when you want to upgrade, they can get a bigger sale. If this isn't enough about memory, you also need to consider whether your motherboard uses 32-pin or 72-pin chips, parity or non-parity, SIMMS or DIMMs, FPM, EDO, SDRAM, speed, etc. The book that comes with your motherboard will explain all of this in detail and tell you exactly what you need. If you don't have that book. Memory speed is measured in nanoseconds. Normally the faster (lower number), the better. You need 60ns memory for computers with a 66 MHZ I/O bus. Above 66 MHZ, you need to consider switching to SDRAM. There's a limit based on your processor speed where faster memory isn't going to do anything for you, but sometime in the future, you may want to upgrade your processor requiring faster memory. If your memory isn't fast enough, the processor may have to slow down to accomodate the memory.

Memory	Type	Number per bank
Fast Page Mode (FPM)	SIMM	2
Extended Data Out (EDO)	SIMM	2
Extended Data Out (EDO)	DIMM	1
Synchronous Dynamic Random Access Memory (SDRAM)	DIMM	1

With faster memory chips, such as SDRAM chips, quality starts becoming very important. The less the number of chips on the board is usually better. There's also ECC SDRAM chips which have Error Correcting Code built-in and EEPROM SDRAM chips which have code on the chips to indicate to the CPU the chip specifications. Some good memory manufacturers are Corsair and Micron (Crucial).