Random Access Memory (RAM) type…

RAM is the type of memory your computer uses to run programs. It is not the storage capacity of the computer, but the capacity of the computer to keep open multiple programs at the same time.

Most desktops and notebooks use one of four popular types of dynamic random access memory (DRAM) for the main system memory (SDRAM, DDR, DDR2, and DDR3).

SDRAM (synchronous dynamic random access memory)


Above PC2100 DDR. Below PC133 SDR.

· Single data rate (SDR) SDRAM is the older type of memory, commonly used in computers prior to 2002.

DDR (double data rate)

· Double data rate (DDR) SDRAM hit the mainstream computer market around 2002 and is a straightforward evolution from SDR SDRAM. The most significant difference between DDR and SDR is that DDR reads data on both the rising and falling edges of the clock signal, enabling a DDR memory module to transfer data twice as fast as an SDR memory module.

DDR2

· Systems implementing the follow-on technology to DDR, called DDR2 began to appear in mid-2004. DDR2 achieves speeds beyond that of DDR, delivering bandwidth of up to 8.5 GB per second. Frequently, DDR2 based systems can use memory installed in pairs to run in "dual channel mode" to increase memory throughput even further.

DDR3

· The latest generation of memory technology, DDR3, began to appear in systems in late 2007. DDR3 is an evolutionary step beyond DDR2 and operates at lower voltages, thereby consuming less power, and can transfer data at rates up to 12.8 GB per second.

So secara umumnya DDR3 2X ganda lebih laju daripada DDR2 RAM, 4X ganda lebih laju drpd DDR RAM, dan 8X ganda lebih laju daripada SDR RAM…….

DDR3 ada banyak kebaikan selain drpd speed lebih pantas berbanding RAM yg trdahulu, antara klebihan yg laen ialah kurang penggunaan kuasa, kurang suhu oprerasi (lower operating temperatures), lower latencies, dll… Disadvantage DDR3 plak ialah lebih mahal, x compatible dgn socket DDR2, n memerlukan motherboard baru dan lbih mahal utk ia beroperasi…

Ini disebabkan kebanyakkan motherboard direka utk support satu jenis memory sahaja…so xleh la mix and match SDRAM, DDR, DDR2 @ DDR3 dalam satu motherboard yg sama,…diorg xkan berfugsi dan xkan fit pown dalam satu soket yg sama…..ok

p/s* credit to : http://www.crucial.com/kb/answer.aspx?qid=3773

http://techmblog.blogspot.com/2011/03/ram.html

http://www.ehow.com/facts_5013494_difference-between-ddr-ddr-memory.html