What is SDRAM Memory?

SDRAM (Synchronous Dynamic Random-Access Memory) is what most computers were equipped with from 1996-2002. Its speed rating is given in MHz to easily compare it to system board bus speeds. This type of memory synchronizes its input and output signals with the incoming clock that is used in the system board. By doing so, data transactions can continually take place with each successive rising edge of the clock.

How can I tell the difference between SDRAM and DDR?

A DDR SDRAM module has 184 pins for the dual inline memory modules (DIMMs) of the desktop computer. SD RAM has 168 pins and the DDR2 SDRAM, which is the next version of DDR SDRAM, has 240. It is easy to tell the DDR and SD models apart, simply look at the number of notches on the memory card. The DDR version has one and the SD version has two.

Can you mix and match ECC and non-parity modules?

No. When adding new memory, you need to match what is already in your system. You can determine if your system has parity by simply counting the number of black memory chips on each module. Parity and ECC memory modules have a chip count divisible by three or five. Any chip count not divisible by three or five indicates a non-parity memory module.

Can DDR and SDRAM be used in the same system at the same time?

No. Even though there are systems that support both technologies, you can't have DDR and SDRAM in the same system at the same time. You'll have to choose one or the other.

Does it matter which slots I plug my new module in?

In general, you will get the best performance if you put the largest module (in megabytes) in the lowest-numbered slot. For example, if your computer comes with 128MB of removable memory and you want to add 256MB, it would be best to put the 256MB module into slot 0 and the 128MB module into slot 1.

What is the difference between RDRAM & SDRAM? Which one do I need?

RDRAM (Rambus dynamic random access memory) and SDRAM (synchronous dynamic random access memory) are two different types of memory technology. RDRAM is newer and in some cases faster, but SDRAM is less expensive. The most important thing to know is that you cannot use RDRAM in a system designed for SDRAM or vice versa. The two types of modules are different sizes and shapes, so they won't even fit into the same memory slots. You should buy whichever memory type was designed for your system