Corsair TWIN2X1024 5400C4 PRO DDR2 Review

corsair-twinx1024

Introduction

DDR has been around now for a good number of years and since its birth I started hearing people ask when is DDR2 going to be out? DDR2 has finally emerged and will eventually take over current DDR like SDRAM was taken over by DDR a few years back. Currently there are only a small number of Intel motherboards and no AMD motherboards that can use DDR2. This fact leaves users with the question of should I upgrade or wait a while?

What are the major differences between DDR1 and DDR2?
Current DDR uses a 2-bit prefetch while DDR2 implements a 4-bit prefetch, prefetching is gathering data before it is needed. This basically means that every bus cycle 4 bits of data will be transmitted instead of 2. Of course this probably leads you to wondering why the overall bandwidth isn’t doubled as well. The simplest answer I can give is because information is only requested half as often. DDR2 also utilizes a FBGA (Fine Ball Grid Array) while DDR uses a TSOP-II (Thin Small-Outline Package). The FBGA uses a find pitch ball arrangement on the underside of the package, where the TSOP has leads protruding from the sides of the package. Because the contact point of the FBGA is on the bottom of the package, the package can be made smaller than the TSOP.

New Features
There are also a few new features for DDR 2 that are good improvements over current DDR. With original DDR excess signal noise is eliminated using terminating resistors that are built into the motherboard. In DDR2, resistors are still used eliminate the excess noise, however these resistors are built into each of the memory chips on the module which keeps them closer to the source of the noise. This is intended to reduce interference within the chip.

Posted CAS and additive latency are two new technologies that work together to prevent data collisions within the memory as well as better utilizing the data transferring more read/write within each clock cycle. Off-chip driver calibration (OCD) is another new technology which provides the option of tightening the variance of the pull-up and pull-down output driver at 18 ohms nominal. This increases the signal integrity and the system timing margin. The table below is a summary of the major differences between DDR and DDR2.

DDR
DDR2
Data Bus
64 bits
64 bits
Data Rate
200/266/333/400 Mbps
400/533/667 Mbps
Bus Frequency
100/133/166/200 MHz
200/266/333 MHz
DRAM Frequency
100/133/166/200 MHz
100/133/166 MHz
Package Type
TSOP-II
FGBA
Densities
256 MB, 512 MB, 1 GB
256 MB, 512 MB, 1 GB
Voltage
2.5 volts
1.8 volts
Prefetch Size
2 bit
4 bit
Burst Length
2/4/8
4/8
CAS Latency
1.5, 2, 2.5
3+, 4, 5
Write Latency
1T
Read Latency-1
Packaging
TSOP (II), TBGA
FBGA

The TWIN2X1024-5400C4PRO is a 1024 MByte matched pair of 240-pin DDR2 SDRAM DIMMs. This memory has been verified to operate at 675MHz at the low latencies of 4-4-4-12 with 1.9v. Each module pair is tested together in an Intel-based motherboard at 675MHz and packaged together upon completion.


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The front and back of the modules are basically identical; the only difference is the specification sticker on one side. This DDR2 has platinum heat spreaders with 24 activity LEDs built into them so you can see your memory in action. This feature will be looked at in more detail later in the review.

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The memory comes with installation instructions in five languages incase you are unsure on how to install them. You also get a flier about their monthly email newsletter which you can sign up for on the main page of Corsair’s website.

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