OCZ DDR2 PC-5400 Memory Review - PAGE 1

Introduction

The advent of the 915/925x chipsets from Intel paved the way for a sea of changes including BTX power connectors, PCI Express, LGA775 and DDR2. One of the growing bottlenecks in the PC platform has been memory speeds. It is a fact that the gap between processor and memory speeds has continually grown wider since the inception of the PC. In the last five years, the biggest transition in terms of memory performance is the transition from SDR to DDR. There was also Intel's push towards RAMBUS but it has since dropped off the radar for the mainstream market therefore it will be left out of the discussion.

The introduction of DDR to the mainstream in 2001 came with VIA's KT266 chipset and has been the memory of choice since then with Intel eventually throwing in their lot with DDR also. After roughly 3.5 years, Intel has started to push for another transition with memory in DDR2. DDR2 is still based upon the principles of the original DDR specification. Instead of just transferring data on one edge of the clock cycle, DDR and DDR2 transfer data on both the rising and falling edge of the clock cycle. At the most basic level, DDR2 is just a speed enhanced version of DDR with some architectural changes. Some of these changes can already be seen; the most obvious one to end users is the transition to BGA memory, which is has been found on video cards for some time now. The voltage requirements of DDR2 are down from 2.5 volts to 1.8. We have a nice little chart from our X800 preview that outlines some of the more technical differences between DDR and DDR2.

Today we have OCZ's newest flagship product - DDR2 PC2-5400 dual channel memory. Although it 'only' runs at 667 Mhz, the moniker implies the stock speed runs at 675 Mhz. Although it runs at the same (or slower speeds due to timings) as Crucial/Corsair's DDR2-5300, It has another 100 points added to its name. Not a big deal since enthusiasts at this level will likely research heavily before purchasing, but it's an interesting little tidbit since it was always known as DD2-5300 before its release.

Specifications

There are a few things to note here. One of the tradeoffs of DDR2 is the significantly higher latencies associated with it compared to DDR. CAS latencies of DDR1 are usually in the range of 2-3, with most of the faster memory modules being CAS 2.5 or CAS 3.0. In DDR2 we see CAS latencies of 4 and even 5. This is slightly misleading and you should NOT base your opinion of DDR2 performance on CAS - CAS latency is relative to the speed of the memory and latencies of 4 or 5 on DDR2 is actually no worse than lower CAS latencies on regular DDR.

Image courtesy of Intel and Samsung

One thing that all overclockers will really appreciate is OCZ's generous warranty: the memory is covered by a lifetime warranty, not only at stock speed and voltages but up to 2.2 volts, a significant increase over the stock 1.8V of DDR2! PC5400 is rated at 667 Mhz. This will be a marked difference between this and generic memory. OCZ is a performance oriented company with policies that reflect this and we commend them for the added hardcore support.

A stick of DDR2 and DDR. Notice the key is slightly offset