Q: What is DDR SDRAM?
A: DDR SDRAM stands for Double Data Rate-Synchronous DRAM, a type of SDRAM that supports data transfers on both edges of each clock cycle which effectively doubling the memory chip's data throughput.
Q: What is Dual Channel Memory?
A: Dual channel architecture simply takes the existing RAM technology to break the single channel bottleneck of memory bandwidth. With a second parallel channel added into chipset, the bandwidth of memory has greatly increased to boost up overall system performace.
In order to use Dual Channel Memory, your motherboard has to be capable of supporting this technique and you will also need two equal memory modules.
Q: What is CAS Latency?
A: Besides the speed of DDR1 and DDR2, there is additional information that tells you the memory performance. Those information are numbers like 2.5-6-3-3 1T, and the lower the better.1.2.5-6-3-3-1T
2.CL-tRas-tRCD-tRP-CMD
CL: CAS Latency. The time it takes between a command having been sent to the memory and when it begins to reply to it. It is the time it takes between the processor asking for some data from the memory and it returning it.
tRCD: RAS to CAS Delay. The time it takes between the activation of the line (RAS) and the column (CAS) where the data are stored in the matrix.
tRP: RAS Precharge. The time it takes between disabling the access to a line of data and begin of the access another line data.
tRAS: Active to Precharge Delay. How long the memory has to wait until the next access to the memory can be initiated.
CMD: Command Rate. The time it takes between the memory chip having been activated and when the first command may be sent to the memory. Sometimes this value is not informed. It usually is T1 (1 clock cycle) or T2 (2 clock cycles).
