Random-access memory

RAM is a required hardware component in most computer or processing machines. It imposes as a temporary data storage which allows its data to be accessed with no specific order. RAM is technically called Double data rate synchronous dynamic random-access memory (DDR SDRAM).

Ram Types

whereisram.jpg There are different types of RAM available in the market, but older versions are much slower than the ones that came out later. Neither versions are backwards or forwards compatible, meaning that you cannot use a specific RAM type on a computer designed for another type. The reason for this is because that Pin sizes are different on ram (the connectors), voltage and power usage are much different and the way how the memory module is designed so that it cannot fit inside the socket of a Motherboard.


sdrram.jpg Single Data Rate or SDR is extremely obsolete with no purpose of using it anymore in today worlds market. It was the one of the first Synchronous Memory architecture and the only SDRAM that existed after it’s obsoletion with no plans to upgrade it, as DDR ram replaced and surpassed its functionalities. Single Data Rate means that it can transfer one machine word (16 bits for the x86 architecture) during one CPU cycle. It mostly used in the 90’s for most computers until up to the Pentium 3 processor. Common speeds includes PC-100 and PC-133 which ran on clock speeds of 100MHz and 133MHz respectively.


Double Data Rate SDRAM is a direct successor to Single Data Rate SDRAM or SDR SDRAM, which had doubled clock speeds per CPU cycle. DDR doubled speeds over SDR SDRAM architectures. DDR RAM have been used in the Pentium 4 and AMD Athlon CPU. In market, DDR RAM have always been told that speeds are always doubled than it’s preceder. The marketed speeds are DDR-200, DDR-266, DDR-333 and DDR-400. This was actually wrong, the real speeds are 100MHz, 133MHz, 166MHz and 200MHz.


DDR2 SDRAM is an Improvement to its predecessor. Improvements were made in bandwidth, clock speeds, and voltages. This dramatically increased in system performance, and made most home computers much more faster and easier to use. DDR2 was common for PC’s running Pentium 4 Prescott and later including Intel Core, and AMD Athlon 64. Speeds were DDR2-400, DDR2-533, DDR2-667, DDR2-800 and DDR2-1066. All the modules are doubled the speed than its previous DDR type.


DDR3 SDRAM finalized in 2007 and primarily increased clock speeds and reduced voltages at the same time. DDR3 only had a significant increase in speed though in real world applications (only on architectures that support both standards). Although, the DDR3 memory is almost required when using the latest AMD or Intel CPU (790/AM3 and X58/P55). Speeds for DDR3 includes DDR3-1066, DDR3-1333, DDR3-1600, DDR3-1800 and DDR3-2000.


ddr4.jpg DDR4 SDRAM was suggested first in 2008, but delayed due to advances in technology. Mass production is predicted to happen by 2015, hoping to replace 50% of the markets RAM. As of 2013, it was delayed to 2016. DDR4 speeds first created by Samsung in 2013 showed DDR4-2133 and DDR4-2400 with 40% less power than a DDR3 module. The maximum speed for DDR4 reported to be DDR4-4266.

RAM in Laptops

laptopram.jpg Laptop RAM is called small outline dual inline memory module or SODIMM instead of the normal DDR SDRAM. SODIMM RAM are usually in computers with limited space, like Laptop, Notebooks, PC’s with a mini-ITX case. They are also found sometimes in High End printers and Rarely in routers.


  • 100-pin SO-DIMMs have two notches on one far to one side, and one near the middle.
  • 144-pin SO-DIMMs have a single notch near the middle
  • 200-pin SO-DIMMs (DDR2).
  • 204-pin SO-DIMMs (DDR3).
  • 256-pin SO-DIMMs (DDR4).

Computers | Hardware

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