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HOME  Memory #739 - Crucial Ballistix PC2-6400 Memory
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#739 - Crucial Ballistix PC2-6400 Memory |
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Written by Zach Jeffers
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Monday, 09 October 2006 |
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Page 3 of 6
Specifications:
The Crucial Ballistix memory for review today has a speed of 800 MHz (PC2-6400), a CAS Latency of 4 and a timing of 4-4-4-12.
What is DDR? DDR stands for Double Data Rate and has been around for a while. The electronic signal that goes through the memory looks like a line of waves going up and down. In the days of long ago, these signals would carry only one packet of information on the top of the signal wave. With DDR, engineers have included an additional packet of information to the bottom of that wave. This effectively gives you twice the information through put on the same channel of RAM.
So then, you ask, what is Dual Channel or DDR2 RAM? On the motherboard, or these days on the CPU, is a memory controller. DDR1 only had one 64bit controller to direct and transfer data with the memory modules. With Dual Channel memory, the board or CPU has two 64bit memory controllers working the data; thus the name tag of Dual Channel.
For a description of the differences of DDR and DDR2, here is what our own Gameman, Rodney, wrote in his last Crucial review, "To begin, the maximum Data Rate is different (400MHz for DDR vs. 667MHz for DDR2), Bus Frequency (200MHz vs. 333MHz), DRAM Frequency (200MHz vs. 166MHz), Package Type (TSOP-II vs. FBGA), Voltage (~2.5 vs. 1.8), Prefetch Size (2 bits vs. 4 bits) and a CAS Latency (which varies quite a bit but in general 2.5 for DDR vs. 4 for DDR2 memory). The on-die termination is different as well. To eliminate signal noise, DDR uses transistors that are on the motherboard whereas for DDR2 it’s on each memory chip. The Off Chip Driver Calibration on DDR2 memory also increases signal integrity."
Also, remember that DDR2 and DDR1 are roughly the same size, but have a different slot type and are not cross compatible!
Specifications:
- Module Size: 2GB kit (1GBx2)
- Package: Ballistix 240-pin DIMM
- Feature: DDR2 PC2-6400
- Configuration: 128Meg x 64
- DIMM Type: UNBUFFERED
- Error Checking: NON-ECC
- Speed: DDR2-800
- Voltage: 2.2V
- Memory Timings: 4-4-4-12
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