DDR memory, PC2100 (DDR266), PC2700 (DDR333), PC3200 (DDR400), PC4200 (DDR533). A quick look at DDR memory, what is DDR memory ? what some of the terms mean & which DDR memory to buy?
What is DDR Memory?
DDR
memory, or Double Data Rate memory, is a new high
performance type of memory that runs at twice the speed of normal SDRAM.
This DDR SDRAM is ideally suited to the latest high performance processors
to increase overall system speed. The faster the memory, the quicker instructions
can be passed to the processor. DDR memory provides roughly a 15% boost
in performance compared to regular SDRAM. With DDR memory now in the affordable
price range, and motherboard manufacturers phasing out SDRAM on nearly every
new board, it looks like DDR is definitely here to stay. Even corporate
giant Intel dumped the once-all-mighty RAMBUS, and opted for integration
of DDR support into their chipsets and motherboards, only to join forces
and rise to power with the P4. Memory manufacturers are doing a good job
of producing high-quality RAM for demanding systems and the ever-changing
industry.
DDR memory
is the latest in high-performance memory module technological advances.
It offers twice the data bandwidth of conventional PC100 or PC133
SDRAM, and is particularly well suited for high-performance servers
and workstations, which need optimal CPU-memory performance. Double Data
Rate (DDR) SDRAM (AKA SDRAMII) is precisely what the name implies. A clock
cycle can be represented as a square wave, with the rising edge defined
as the transition from "0" to "1", and the falling edge
as "1" to "0". In SDRAM, only one of these wave edges
is used, but DDR SDRAM references both, effectively doubling the rate of
data transmission. Unlike 168-pin SDRAM, DDR SDRAM utilizes a 184-pin
plug. Although the basic motherboard technology does not need to
be changed, DDR SDRAM is not backward compatible on motherboards designed
for SDRAM.
DDR memory can only be used in systems designed specifically for DDR memory
DDR Memory terms explained
What is DDR memory CAS Latency?
CAS Latency is the time needed (clock cycles) to address the data column. CAS is the Column Address Strobe. Thus CL2.5 is quicker than CL3. (2.5 < 3) But, once the first piece of data is processed the rest of the data is processed at equal speeds. Latency only affects the initial burst or fetch of data.RAS is the Row Address Strobe. Abbreviated RAS, a signal, or strobe, sent by the processor to a DRAM circuit to activate a row address. DRAM stores data in a series of rows and columns, similar in theory to a spreadsheet, and each cell where a data bit is stored exists in both a row and a column. A processor uses RAS and CAS (column address strobe) signals to retrieve data from DRAM. When data is needed, the processor activates the RAS line to specify the row where the data is needed, and then activates the CAS line to specify the column. Combined, the two signals locate the data stored in DRAM.
What is DDR memory?
Why DDR Memory? What DDR Memory to buy?RAM Influence on Computer Performance
Memory Chipset Specifics (Intel, Via Apollo, SIS, AMD Chipsets)
How
Computer Memory Works?
How
much RAM is enough?
System
RAM Upgrade Issues
Websites
that sell Memory Upgrades
