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#672 - Mushkin PC2-6400 DDR2 Memory |
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Written by Rodney Reynolds
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Saturday, 13 May 2006 |
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Page 3 of 6
Specifications:
The speed on
this memory is 800MHz DDR or PC-6400; it has a CAS of 4, and
a memory timing of 4-4-3-10 (CAS-TRCD-TRP-TRAS).
Now what does DDR and CAS mean?
DDR
stands for Double Date Rate and that means it doubles the
bandwidth of the memory by transferring data twice as fast
on both the rising and falling of the clock cycle.
CAS
stands for Column Access Select or Column Access Strobe and
that essentially means the number of cycles for the memory
to get information and then process that information. Also
keep in mind that a lower CAS is much better than a higher CAS,
so try and keep CAS as low as possible when overclocking.
This memory is also Dual Channel which means better overall
memory bandwidth resulting in superior performance. In order
to benefit from this technology you will need to have a dual
channel motherboard. Non-dual channel motherboards do not
have two fully independent 64-bit memory controllers but
dual channel boards do, which means they have a 128-bit
memory interface. They can be installed singly, but
obviously performance will be much less at the same MHz.
Please remember that this memory is DDR2 and it does differ
from DDR memory in a number of ways. The following
explanation below goes over the general differences. It does not take into
account some of
the fast DDR/DDR2 memory on the market, but it is designed to
help you distinguish between the two:
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.
While 240-pin DDR2, 184-pin DDR and the older style 168-pin
DIMM memory are all
approximately the same size, the 240-pin DIMMs and 184-pin
DIMMs have only one notch within the row of pins. The notch
in a 240-pin DDR2 DIMM is slightly more toward the center of
the module. Please keep in mind that DDR2 memory is not
backward compatible and will only fit motherboards
specifically designed for it.
Now, what�s the bottom line on this new DDR2 memory? Is it
faster than DDR at the same speed? The short answer is,
currently, not really. However, remember DDR2 is fairly new to the
market so it will take some time for hardware and software
companies to fully utilize its overclock ability, superior
performance and bandwidth. One notable improvement in DDR2
memory
is the tighter memory timing. That's crucial for better
performance.
Details Specifications:
Speed: PC2 6400 or 800 DDR2 (400MHz)
Size: 2GB (1GB x 2)
Part Number: 991523
Configuration: (2pcs) 128M x 64 , non-Reg., no-ECC
Chips: ? (Will update later)
Latency: 4-4-3-10 (CAS-TRCD-TRP-TRAS)
Package Type: 240 DIMM
Heat Spreader: Aluminum Heatspreader
Voltage: 1.9-2.1V
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