DDR Memory / SDRAM / RAM 256 mhz/ ddr 533 mhz 1. 2-3 lead time 2. full compatible 3. 5 years wrantty 4. Professional DDR Memory / SDRAM / RAM 256 mhz/ ddr 533 mhzDDR1,DDR2,DDR3Desktop Computer,laptop computer128MB/256MB/512MB/1G/2G/4G  1) DDR 400/333 & DDRII 533/667/800 & DDRIII  1066/1333 MHz2) 168/184/240-pin socket type dual in line memory module (DIMM) 3) 2.6V power supply4) Data rate: 400/333/533/667/800Mbps (max ) 5) 2.5 V (SSTL-2 compatible) I/O for DDR I products, 1.8Vpower supply for DDR II products 6) Double-data-rate architecture, two data transfers per clock cycle. 7) Bi-directional, differential data strobe (DQS) is transmitted/received with data, to be used in capturing data at the receiver8) Data inputs and outputs are synchronized with DQS  9) DQS is edge aligned with data for read, center aligned with data for write.10) Differential clock inputs (CK and CK).11) DLL aligns DQ and DQS transitions with CK transitions.12) Commands entered on each positive CK edge: Data and data mask referenced to both edges of DQS13) Four internal banks for concurrent operation (component) 14) Data mask(DM) for write data 15) Auto precharge option for each burst access16) Programmable burst length: 2, 4, 8 17) Programmable/CAS latency (CL): 3 18) Programmable output driver strength: Normal/weak19) Refresh cycles: (8192 refresh cycles/64ms) 20) 7.8US maximum average periodic refresh interval 21) Posted CAS by programmable additive latency for better command and data bus efficiency 22) Off-chip-driver impedance adjustment and on-die-termination for better signal quality 23) DQS can be disabled for single-ended data strobe operation24) 2 variations of refresh 25) Auto refresh.26) Self refres