What is DDR SDRAM?
DDR SDRAM stands for Double Data Rate synchronous dynamic random access memory. It is a type of integrated memory circuit used in desktop computers and laptops. It can achieve almost double the bandwidth of it's predecessor SDRAM without needing to up the operating clock rate.
To work out the speed of DDR you can do so by following this simple example:
Lets take a ddr memory chip that runs at 200 mhz, we then times that by two because of double data rate which is equalled to 400mhz and then x that by 64 because this is how many bits are transferred each time. So that now comes to 25600 we then divide that by 8 which is how many bits are in a byte to get a total of 3200 MB/s.
So the equation is:
Memory speed x 2 x 64 / 8 = Memory transfer rate
It might be interesting to point that ddr memory modules are all designed with the same architecture so the only real difference is the speed at which they have been set to run at by the manufacturer, however the speed at which is set is based on testing and thus it's guarantee to run at that particular speed. Based on these principles it is quite possible to run a ddr memory chip at a faster speed or even a slower speed.
DDR SDRAM can be used within desktop computers as well as laptop computers as already stated. But there is one fundamental difference with regards to the number pins found on each type. With DDR SDRAM for desktop computers you will find 184 pins and for laptop computers the number of pins are 200. DDR SDRAM can also be confused with regular SDRAM but to tell the difference, SDRAM only has 168 pins with two notches on the bottom of the dimm (dual inline memory module) DDR SDRAM only has one notch. Also SDRAM runs at a higher voltage normally 3.3v where as DDR SDRAM runs at 2.5V.
Many new chipsets use these memory types in dual-channel configurations, which doubles or quadruples the effective bandwidth.
High density Memory
Within the context in the One GB non-ECC pc 3200 SDRAM module, there's hardly any visually to distinguish low density from high density Memory. High density DDR Memory modules may, such as its low density alternative, typically be double-sided along with 8 512 Mbit chips each side. The actual distinction is always that every chip, rather than being structured in a 64M×8 configuration will be structured using 128 Mbits plus a data width of Four bits, or even 128M×4. To deeper construe the matter, various Memory can be called 128M×8, and is also known as high density.
The majority of high density Pc 3200 chips usually are put together using Samsung chips. All these chips come with the two common 22 × 10 mm (approx.) TSOP2 as well as a small squarer 12 × 9 mm (approx.) FBGA package sizes. High density Samsung chips are usually determined by numbers on every chip. If the sixth as well as the 7th characters are 04 (for instance K5H410438D-UCCC) then the particular chips will most certainly be ×4 and high density. When the sixth and 7th characters are 08 then the chips will be ×8 and therefore low density.
High density Ram memory modules have been built to be utilised in registered ram chips for servers. Due to this fact, overall performance or response times could suffer whenever used with a desktop computer or perhaps a workstation. JEDEC standards don't apply to high-density DDR Memory within desktop computer implementations. JEDEC's specialized documentation, nonetheless, facilitates 128M×4 semiconductors as such that contradicts 128×4 being labeled as high density. Therefore, high density is really a relative name, which in turn can often identify memory that is not necessarily recognized by a certain motherboard's ram controller.