er than SDRAM.
12. SB SRAM (Synchronous Burst SRAM)
General SRAM is not synchronous, to adapt the faster and faster CPU, the working plus should become synchronous with system, this is the reason why SB SRAM is created.
13. PB SRAM (Pipeline Burst SRAM)
The great improvement of CPU external frequency speed proposes a higher requirement for the matched memory, pipeline burst SRAM takes the place of synchronous burst SRAM, it is inevitable, because it could effectively prolong accessing time plus, finally improve visit speed effectively.
14. DDR SDRAM (Double Data Rate SDRAM)
 
As the replacement of SDRAM, it has two features: one is the speed is twice than SDRAM; the second is that it adopts DLL (Delay Locked Loop) to provide a data filtering signal. This is the mainstream mode so far on the market.
15. SLDRAM (Synchronize Link DRAM)
 
   This is an extended SDRAM structure memory, at the time adding move advanced sync circuit, there’s improvement on logical control circuit. However, because of technical display, it’s difficult to use practically.
16. CDRAM (CACHED DRAM)
This is a patent technology first developed by Mitsubishi Electronic Company, which inserts a SRAM as L2 Cache between DRAM chip’s external pins and internal DRAM. Currently, almost all CPU have L1 Cache to increase efficiency, as the multiplied increase of CPU clock frequency, Cache would not cause big impact on system performance more and more, while the L2 Cache provided by Cache DRAM could fill the sho