SK hynix Inc. is a South Korean supplier of dynamic random-access memory (DRAM) chips and flash memory chips. Hynix is the world's second-largest memory chipmaker and the world's sixth largest semiconductor company. Founded as Hyundai Electronic Industrial Co., Ltd. in 1983 and known as Hyundai Electronics, the company has manufacturing sites in Korea, the United States, mainland China and Taiwan. In 2012, when SK Telecom became its major shareholder, Hynix merged with SK Group.
A 512 MB DDR 333 MHz SO-DIMM Hynix memory module
Dynamic random-access memory
Dynamic random-access memory is a type of random-access semiconductor memory that stores each bit of data in a memory cell, usually consisting of a tiny capacitor and a transistor, both typically based on metal–oxide–semiconductor (MOS) technology. While most DRAM memory cell designs use a capacitor and transistor, some only use two transistors. In the designs where a capacitor is used, the capacitor can either be charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1. The electric charge on the capacitors gradually leaks away; without intervention the data on the capacitor would soon be lost. To prevent this, DRAM requires an external memory refresh circuit which periodically rewrites the data in the capacitors, restoring them to their original charge. This refresh process is the defining characteristic of dynamic random-access memory, in contrast to static random-access memory (SRAM) which does not require data to be refreshed. Unlike flash memory, DRAM is volatile memory, since it loses its data quickly when power is removed. However, DRAM does exhibit limited data remanence.
Motherboard of the NeXTcube computer, 1990, with 64 MiB main memory DRAM (top left) and 256 KiB of VRAM (lower edge, right of middle)
A pair of 32 MB EDO DRAM modules
A 512-MBit Qimonda GDDR3 SDRAM package
Inside a Samsung GDDR3 256-MBit package