Home
 
  Clearance
 
  Computers & Devices
 
  Displays & Peripherals
 
  Consumables & Media
 
  PC Components
 
  Software
 
  Networking
 
  Electronics
 
FAQs | contact us
 


PC Components»Memory»DDR2 Modules

GEIL 512MB DDR2 667 CL5.0 08 CHIP BRUSH ALUMINUM RET
 
 
GX25125300LX
 
Product No: 9926
 
£ 7.79     
inc VAT price: £ 9.15

In stock:  5
 
 
Like all SDRAM implementations, DDR2 stores memory in memory cells that are activated with the use of a clock signal to synchronize their operation with an external data bus. Like DDR before it, DDR2 cells transfer data both on the rising and falling edge of the clock (a technique called "dual pumping"). The key difference between DDR and DDR2 is that in DDR2 the bus is clocked at twice the speed of the memory cells, so four words of data can be transferred per memory cell cycle. Thus, without speeding up the memory cells themselves, DDR2 can effectively operate at twice the bus speed of DDR.

DDR2's bus frequency is boosted by electrical interface improvements, on-die termination, prefetch buffers and off-chip drivers. However, latency is greatly increased as a trade-off. The DDR2 prefetch buffer is 4 bits deep, whereas it is 2 bits deep for DDR and 8 bits deep for DDR3. While DDR SDRAM has typical read latencies of between 2 and 3 bus cycles, DDR2 may have read latencies between 4 and 6 cycles. Thus, DDR2 memory must be operated at twice the bus speed to achieve the same latency.

Another cost of the increased speed is the requirement that the chips are packaged in a more expensive and more difficult to assemble BGA package as compared to the TSSOP package of the previous memory generations such as DDR and SDRAM. This packaging change was necessary to maintain signal integrity at higher speeds.

Power savings are achieved primarily due to an improved manufacturing process through die shrinkage, resulting in a drop in operating voltage (1.8 V compared to DDR's 2.5 V). The lower memory clock frequency may also enable power reductions in applications that do not require the highest available speed.
 
Products from the same brand  
 
GEIL 4GB DDR2 1066 CL5.0 DUAL CHANNEL EVOONE RET
Product No: 223586
GeIL 4 £87.00875
inc. vat 102.24
view and buy
 
 
GEIL 4GB DDR2 1066 CL5.0 D/C MET ORA ALU
Product No: 227989
GeIL 7 £69.54825
inc. vat 81.72
view and buy
 
 
GEIL 4GB DDR2 1066 CL5.0 DUAL CHANNEL BLACK DRAGON RET
Product No: 173311
GeIL 11 £74.166
inc. vat 87.15
view and buy
 
 
GEIL 4GB DDR2 800 CL6.0 DUAL CHANNEL BRUSH ALUMINUM RET
Product No: 111498
GeIL 32 £35.203
inc. vat 41.36
view and buy
 
 
GEIL 8GB DDR2 800 CL5.0 QUAD CHANNEL EVOONE RET
Product No: 129278
GeIL 3 £90.052
inc. vat 105.81
view and buy
 
 
GEIL 2GB DDR2 667 CL5.0 DUAL CHANNEL BRUSH ALUMINUM RET
Product No: 157116
GeIL 16 £20.08075
inc. vat 23.59
view and buy
 
 

SHOPPING CART
cart is empty