OCZ 3500EB: The Importance of Balanced Memory Timingsby Wesley Fink on April 7, 2004 12:04 AM EST
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Conventional wisdom in the memory industry in recent years has been that CAS latency was the most important specification in memory performance. This has spawned a whole group of high-end DDR products with acronyms like "LL" for Low-Latency, "EL" for Enhanced Latency, and other labels with the message that Latency was the lowest possible and performance was the highest that you could buy. This whole thinking reached a frenzy in the DDR market around DDR333 to DDR400 where the message became so pervasive that if a memory was not CAS 2, then it was not the best performance that you could get.
As DDR memory frequencies have soared beyond DDR400 to DDR500, DDR550, and even higher, we have seen memory modules appear with timings of 3-4-4 at these higher memory speeds. Since customers were now firmly indoctrinated into the CAS 2 camp, many Enthusiasts complained that the new high-speed memory was only half there because what they really wanted was DDR500 at 2-2-2 timings. Variations on this theme were the "proof" that DDR400 run at 5:4 ratio at CAS 2 could normally meet or beat performance of higher speed DDR500 memory, which used slower CAS 3 timings. The point that was forgotten in this argument was that with all things being equal, DDR500 would always perform faster than DDR400, but technology was not to a point where DDR500 CAS 2 memory could be manufactured. This further reinforced for some the almighty importance of CAS latency.
Several recent developments have caused memory manufacturers to re-examine the importance of CAS latency to performance. First, manufacturers have been unable to produce a DDR500 memory that could run at CAS 2. In fact, the DDR500 modules have not even been able to run also at DDR400 at 2-2-2 timings. Second, Winbond announced their exit from the market, removing DDR400 2-2-2 and even 2-2-3 timings from currently available memory. Third, the development of DDR2 memory, which at DDR533 is being launched with 4-4-4 to 5-5-5 timings. An interesting development with DDR2 is that while memory timings are even slower than the worst DDR timings, the performance can sometimes keep up with DDR because of other internal memory timings. This is not praise for DDR2, but all these developments bring to the forefront that CAS Latency is not the only thing that matters in memory performance, and in fact, it may not even be the most important specification as we move to faster memory.
Into this climate, OCZ has introduced their latest EB, or Enhanced Bandwidth, memory with the claim that CAS 2.5 or 3 can often perform just as well as CAS 2. According to Dr. Michael Schuette of OCZ, "Enhanced Bandwidth technology is an exciting improvement that, at 2.5-2-3 (CL-tRP-tRCD) latencies, allows most applications to use data bandwidth that is the same as that delivered by CL-2 modules." Many of you already know Dr. Michael Schuette from his well-respected Lost Circuits technical website. What you may not know is that Michael is now Director of Technology Development for OCZ.
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Pumpkinierre - Sunday, April 11, 2004 - linkStill waiting for my OCZ IC7 link Wesley
TrogdorJW - Thursday, April 8, 2004 - linkbldkc... Not really. Only people overclocking their CPUs to extreme highs are pushing memory at the 500+ MHz range. The fastest official speeds are still DDR400, and DDR2 will probably be necessary before we gain official support for DDR466 and/or DDR533. I'm just waiting for DDR666.... eeeevil! Oh, wait, they'll call it DDR667 to appease the Bible thumpers.
On a tangent, I'm an active Christian, and I find this "fear" of 666 to be rather absurd. "The number of the beast shall be six hundred sixty-six." Yeah, and the beast is apparently some computer part... or it would be if we had a 666 MHz CPU/RAM/Bus/whatever. Okay, on with life....
bldkc - Wednesday, April 7, 2004 - linkIt wasn't long ago that we were asking the Processor Gods when they were going to catch up to the RAM Gods and use all that big bandwidth they were selling. Well here we are. Now we must pray that the Ram Gods will treat us kindly, and return the favor.
Wesley Fink - Wednesday, April 7, 2004 - linkAdul -
I will include some Athlon 64 results in an upcoming A64 board review. I did check compatibility with A64, which was excellent even on VIA K8T800, which can be very picky about memory and timings. Also took a brief look at A64 performance, and found best performance timings on A64 nF3 were 2.5-2-3-9 as mentioned in the review.
RyanVM - Wednesday, April 7, 2004 - linkAnd what if due to past transgressions, many (including myself) still don't trust anything OCZ puts their name on?
Adul - Wednesday, April 7, 2004 - linkAny chance to get some test results on a Athlon 64 wes?
grunjee - Wednesday, April 7, 2004 - linkWhere the heck can I get some of this stuff??? Been looking and haven't been able to find any.
Great review btw Wesley.
bigtoe33 - Wednesday, April 7, 2004 - linkI have an unbuffered available on bleedinedge forum.
this shows turbo enabled on an IC7.
Spacecomber - Wednesday, April 7, 2004 - linkI was left wondering if you would see the same benefit from the enhanced bandwidth with Athlon Systems as you do with the Pentium 4 system that was used in the benchmarks.
I've gathered that the rule of thumb is that Pentium 4s enjoy all the memory bandwidth that you can feed them, while Athlon XP systems are less bandwidth starved and do better with the lowest latencies you can run.
So, I'm wondering if this new OCZ memory will be of most benefit to people running Pentium 4 systems, especially overclocked 800MHz systems, but less (if any advantage) to Athlon users. I also wonder if there is any difference in benefits between an Athlon 64 and the regular Athlon with this memory, for that matter.
These are the kind of practical questions I'm still left with after reading the article. On the other hand, the article gets high praise for bringing this new memory to our attention.
Wesley Fink - Wednesday, April 7, 2004 - linkPumkinierre -
Our memory test bed is the Asus P4C800-E, and we have not tested EB on the Abit IC7. However, OCZ Tech Support tells us they achieve even better benchmark results with EB on the Abit IC7. I will try to provide a link to their test results on the IC7 later today.