OCZ 3700 GOLD: Building High-Performance Memory
by Wesley Fink on August 7, 2003 8:34 PM EST- Posted in
- Memory
Comparing Memory Bandwidth: UNBuffered Memory Performance
In our article, 'Searching for the Memory Holy Grail — Part 1', we demonstrated that the UNBuffered SiSoft Sandra Memory Test correlated very well with MemTest86 bandwidth results. With all of the Buffering techniques disabled, scores are much lower — sometimes a 50% drop — than the scores you are accustomed to seeing for Sandra Memory tests. However, the unbuffered scores have proven to be a very sensitive measure of memory bandwidth. Regarding memory performance, we will be looking at the maximum stable overclock for the memory and the SiSoft Sandra UNBuffered Memory Test.The idea of the UNBuffered Memory Benchmark is very simple — you merely turn off all memory buffering techniques. Sandra makes this very easy to do. Select 'Memory Benchmark', right-click 'Module Options', and uncheck the nine boxes that are related to buffering.
Please keep in mind that the Crucial DDR333 modules using Samsung memory are single-sided DIMMs. As we illustrated in 'Searching for the Memory Holy Grail — Part 1', the performance of two SS modules is lower than the performance of two DS modules in 875/865 boards, and cannot be directly compared.
All memory tests were run on an Abit IC7, Intel 875 Canterwood motherboard with BIOS revision 1.5, and a 2.4C Pentium 4, 800FSB processor that has reached 290MHz (1160FSB) on this motherboard.
| Crucial DDR333 Samsung SS Performance Intel 875 Chipset, Dual-Channel, Maximum Overclock |
|||
| DDR Memory Speed | Memory Timings | Memory Voltage (vDIMM) |
UNBuffered Sandra 2003 Memory Test (MB/Second) |
| 450 | Maximum SPD 2.5-7-4-4 |
2.7V | 2472 INT 2460 FLT |
| 460 | 3-8-4-4 | 2.8V | 2436 INT 2527 FLT |
Given the ability of this Samsung memory, rated at DDR333 or DDR400, to reach DDR460 at 2.8V, we can fully understand why OCZ chose this as their base memory chip. However, as good as this performance is, it does not match the specified performance of OCZ 3700 GOLD of DDR466, 2.5-7-3-3, at 2.65V. So how does a manufacturer of high-speed memory get from this base performance to the performance of 3700 GOLD?
Lasering for Heat Dissipation
When information about OCZ using Samsung TCB3 chips for 3700 GOLD first appeared, others were asking the same question we were asking: how did OCZ get a memory rated at DDR333/400 to the performance levels of 3700 GOLD — or did they?All memory manufacturers (as well as CPU and chipset manufacturers) "bin" chips. This means that they sort chips by speed capabilities. The top-performing chips are then used in the highest-speed products — the rest going into lower rated products. OCZ explained that, in addition to speed binning, they laser the chips to improve heat dissipation before sorting, using the best chips for OCZ 3700 GOLD. They also released an internal document describing the lasering process and how it improves heat dissipation. The information below is from the released internal document:
"INTERNAL USE ONLY : ENGINEERING DEPT -TW-CA
Thermal modification of standard DDR DRAM TSOP packages , for increased thermal dissipation and speed reclassification.
Note #1 : Reference EL DDR packing specification is linked at /spec/elddr.html
Purpose : Increase speed of ( SEC packaged ) TSOP , through using EL DDR packaging theory. To fill product shortage during die revision change
EL DDR Packaging : by decreasing the thickness of encapsulate (low thermal transfer rate ) we are able to effectively increase heat dissipation in DRAM and thereby increase the effective speed of each IC . Using a third party fabrication and packaging plant this theory has been proven and the (B) die revision OCZ EL DDR die had great success. Average maximum speed increase during stage 2 testing has been verified over 23 MHz.
Proposition: While dies fabricated by 3rd parties for OCZ in 3rd party packaging have proven successful to this point . We feel that to insure our success we should supplement by speed binning large quantities of 3rd party IC's and by physically modifying the package decreased thermal resistance and re-speed grade the ICs using the standard Advantest ATE.
Industry Disclosure: See Ryan Petersen
Process Engineering : See XXXXXXXXX
Process Overview :
Samsung semi will provide die location information , we will be using the DP-7 CO 2 laser to remove the surface material from the package face only average laser cut depth is 7mill . After surface removal the package should be sent to ISE for environmental test and then re-speed graded after speed grade and classification chips will be marked ( standard process) and standard process thereafter."
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Anonymous User - Saturday, August 9, 2003 - link
This coments sections is full of trash, what does any of this have to do with the articleMS - Saturday, August 9, 2003 - link
Kristopher,Then that is Corsair, even though they always fervently denied any such practice. Whenever I talked to Robert Pearce, he claimed that it is basically a random choice of module that goes out. I know for a fact that this is how things have been and still are handled at Mushkin, they don't even have the manpower and setup to cherry pick anything.
Anonymous User - Saturday, August 9, 2003 - link
All I can understand (& know already) is thatyou guys just have to know where to buy the same
stuff they sell you for at least half the price.
I bought modules using the same chips rated as ddr33 - & at oem ddr33 price.
Laser This :).
Ill Just use 2.8 & skip your lasering & Rebadging.
wixt0r - Saturday, August 9, 2003 - link
Geez, such an uproar over this OCZ stuff. The memory works!KristopherKubicki - Saturday, August 9, 2003 - link
MS:I can send you some more evidence if you want? That is pretty much Nicole's job at Corsair to make sure reviewers get the best samples for reviews ;)
Kristopher
MS - Saturday, August 9, 2003 - link
Kristopher, I can assure you that neither Corsair nor Mushkin cherry pick any of their review samples.Wesley, I don't mean to say that OCZ quality is bad at all. All I say is that the "EL" process serves a purpose that is different from what OCZ claims. [grin]
Anonymous User - Saturday, August 9, 2003 - link
After reading the article I was wondering if the el ddr process and lasering was so effective then why don't more people do this? Even why Samsung does explore this route. Then I realized what I missed. they are removing 7mill from the surface of the chip. In the chip world size does matter and when you move from nanometer to millimeter thats HUGE. This approach is very risky. I know to well that some mothboards are finiky with memory and I wonder how well today's boards will work with this aggressive approach.Wesley Fink - Saturday, August 9, 2003 - link
Michael - Your review at Lost Circuits and the less stellar performance of the TCB3 modules I had gave me the idea for the article I did here. There is one VERY important piece of info that you do not share here. You bought retail GOLD, and as you stated in your review conclusion, it DID indeed meet specifications and beyond. We can debate the effectiveness of methods all day, but, in the end, performance and reliability is why we buy memory - whatever the brand.Anyone who doubts that MS found the retail memory met spec can check his review of the OCZ3700 GOLD at Lost Circuits.
KristopherKubicki - Saturday, August 9, 2003 - link
#29 Someone mentioned it earlier. The memory companies are all "nice" but they all have their misgivings. Do you think Mushkin hands you a stick they found laying on the ground in the fab? Any manufacturer gives you creame of the crop products for a review. Thats just common practice.Kristopher
Anonymous User - Saturday, August 9, 2003 - link
#28-that is exactly my problem with this article. Are just supposed to believe that the chips all came out of one pile, and half were lasered and half weren't? I'm sorry, but OCZ hasn't earned any sort of right to be taken at their word. Mushkin or Corsair MAYBE, but certainly not a company with a well established history of buying reviews.