DDR3 Memory Standards: Blurry Lines

[Aaron]

DDR3 Memory Standards: Blurry Lines​

Rated speed, JEDEC, XMP, EPP, overclocking, overvolting... and what it all means


Much confusion has dawned upon many new users.  Purchasing memory is not as easy as it used to be.  Manufacturers have forced belief that their modules run at certain DDR3 standards.  However, what they don't tell you is that these standards [1866, 2133] do not exist.  You're required to overclock, modify timings, and overvoltage the memory modules that have these manufacturer rated speeds.  So when you plug your memory into your computer and boot it up for the first time, do not expect 1600+ speeds the first time around.  You'll at least have to enable XMP/EPP and/or manually configure (timing and voltage) settings in the BIOS.

Now this is where things start to get complicated and full of numbers:

JEDEC:

JEDEC is an industry memory standard specification.  Manufacturers comply with the JEDEC standard by programming the JEDEC profiles into the SPD chips on the memory.  The highest SPD profiles you will find on the market right now are DDR-1333 (some are DDR-1600, but DDR-1333 is the main).  This is because the latest Intel CPU platform [Sandy Bridge - P67] doesn't support higher than DDR-1333.  This will change in the future, as Ivy Bridge supports DDR-1600 I believe.

EPP (Enhanced Performance Profile):

EPP is NVIDIA's higher-level SPD programming extention.  NVIDIA's nForce chipsets can read this SPD extention to provide the much desired "one click overclock."  Change a setting and wala, auto-overclocked memory.

XMP (eXtreme Memory Profile):

XMP is Intel's version of EPP that runs on Intel chipsets.

NOTE:  EPP and XMP have 2 requirements:  your memory MUST have an EPP/XMP profile, and your chipset MUST support XMP/EPP.  There are no exceptions to this rule.

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The point of all this confusion, and why the manufacturers do it


The most obvious question is why do the manufacturers do all this?  Because they want to make more money.  The bigger numbers on the sticker means bigger sales.

You would wonder why JEDEC have allowed Intel and NVIDIA to decimate their standard with their "extensions", but nonetheless this is what we're stuck to dealing with.

<hr>


Example scenarios

Example 1:

You bought a P67 board, 2600k and some DDR-2133 memory.  You build the computer to find that the memory isn't running at its manufacturer's rated speed (2133), so you take the first step:  enabling XMP (this is an Intel chipset, remember) in the BIOS.  However, your memory lacks the XMP profiles in its SPD chip so you can't change the setting.  You would then consult the manufacturer's website for the settings to be used.

Example 2:

You visit the manufacturer's website, and consult their specified timings for your memory.  I've chosen Corsair's Dominator GT 2133C9 in this case (>link here<).  If you go to the tech specs section, you shall notice that the SPD speed is 9-9-9-24, DDR-1333, 1.5V which is a JEDEC standard.  Corsair's "tested" speed is 9-10-9-27, DDR-2133, 1.65V* which is not a JEDEC standard, but is programmed with DDR-2133 as an XMP profile.

What this tells us is that these are DDR-1333 modules overclocked to DDR-2133 and programmed with an XMP profile to support that without manual adjustment.  The actual speed of the module is DDR-1333, but the manufacturer's rated speed is DDR-2133.  Like I said previously, manufacturer's rated speeds require at least entering the BIOS and either; enabling XMP, or manually configuring timings, voltage and speed.

If you bought the Corsair modules and tried to run them on an AMD Phenom II system, you would have to input the timings, voltage and speed manually because AMD chipsets do not support XMP.  This is a common misunderstanding among many AMD-related visitors of the forum.

<hr>


Summarising post and final thoughts


To summarise:

- The JEDEC standard of DDR-1333 is currently the highest support on Intel's Sandy Bridge platform.  Therefore, whether your memory has regular SPD profiles for DDR-1600+ or not, it will NEVER be set at those speeds.
- Understanding the difference between JEDEC standards and manufacturer's rated speeds.  The best hint would be look at the voltage.  *JEDEC standards will always be 1.5V or lower; never 1.65V or higher.
- For your memory to work at its manufacturer's rated speed out the box you must; 1) have an XMP/EPP compatible chipset, and 2) have XMP/EPP profile(s) on the memory.
- AMD users will be unable to take advantage of XMP's convenience since their chipsets do not support it.  They will have to set their settings manually.


I hope that this has explained a lot of things to some people, and increased their understanding.

Thanks for reading.

<hr>


Another question to ask yourself: do you really need more than DDR-1333 to begin with?  Find some answers and draw your own conclusion - >> P67 & RAM Performance -or- Why DDR3-1333 RAM is enough -> Save the money! <<

 

[HU16E]

Thanks Aaron! Thanks 'very' much for taking the time to post this valuable insight & information regarding DDR3 Memory. It's become difficult to counter the juggernaut marketing campaign some of the RAM manufacturers have waged towards the buying public. Using the word 'misleading' may almost be too subtle. Having the honor of being able to help Jack & Bernhard here at the forum with some Sandy Bridge platform RAM speed testing, for gaming, there was close to '0' performance increase from 1333 to 2133 speeds. Copy, read, & write showed improvement, but not by any significant amount.  

 

[Stu]

Well done Aaron, consider this a 'Good Article'!

 

[Frankenputer]

 

[Aaron]

Thanks for the kind comments.

Wrote it in about an hour - no biggie.

 

[ex_forum_user_3]

Stu, please put it in the FAQ.

 

[Bernhard]

Thanks Aaron for clarifying this memory overclocking hype in one concise post. This quest by some to try and undewrite these overclocked speeds as having to be achievable, continues to cause a vast amount of problems. Your contribution should assist to enlighten those that want to understand at least. 

 

[doubleohseven]

An interesting note - I am having problems with my RAM not running at advertised speeds (as some may have seen in my topic).  Both of the kits of RAM I purchased have X.M.P., and with that enabled (and even a little voltage and timings boost), they still do not run at the advertised speeds!

Honestly, "misleading" is an understatement...  it almost seems like there needs to be a class action law suit started... I hate when people say "sue sue sue," but its the only way these major corporations learn their lesson!  What they need to do is advertise their RAM as overclocked RAM, so you go in with the assumption that it may not be fully stable, and have no ability to overclock further.  ALSO, they need to put the chip speed (1033 or 1333, my two chip speeds on my two kits of RAM) on their site for EVERYONE to see, so you know exactly what you are buying! Its our right to know!

Sorry, just had to vent some frustations here. Lol.

 

[ex_forum_user_3]

@doubleohseven, you may want to read this before making more statements that involve lawyers and such: >>Please read and comply with the Forum Rules.<<

Further more, you are totally on the wrong track.

1. The memory controller is INSIDE the CPU, as such the CPU is the engine of your car.
2. The memory controller is GUARANTEED by Intel (AMD is about the same) to do 1333.
3. Memory is the tire of the car, it needs to be fast enough, but if the engine fails to do that speed the tires will NEVER reach their rated speed.
4. The motherboard is the chassis of the car, it provides mounting points but it doesn't power the car.
5. The harddisk is the trunk of the car, it determines how much load you can carry/store
6. The videocard is the windscreen and wipers of the car, the bigger they are the more details you see in gaming
7. The PSU is the petrol-tank of the car, use a too small one and your machine stops way before reaching your target.

Maybe now you have a clue that you are on the wrong track?
Sadly people don't do their homework before buying stuff, as such they do not know what they are buying and end up frustrated because they think something is wrong.

Ram is just 1 component....there is also more to a car then just a tire. :rolleyes_anim:

 

[BryanPearsonOnyx]

Thanks - based on some of what appears here I have gone on to research more carefully what is "supported" in a system and now wish I could have some of the time back I have spent trying to tweak my latest system to hit numbers that are unlikely to matter in real terms.

 

[doubleohseven]

@doubleohseven, you may want to read this before making more statements that involve lawyers and such: >>Please read and comply with the Forum Rules.<<

Further more, you are totally on the wrong track.

1. The memory controller is INSIDE the CPU, as such the CPU is the engine of your car.
2. The memory controller is GUARANTEED by Intel (AMD is about the same) to do 1333.
3. Memory is the tire of the car, it needs to be fast enough, but if the engine fails to do that speed the tires will NEVER reach their rated speed.
4. The motherboard is the chassis of the car, it provides mounting points but it doesn't power the car.
5. The harddisk is the trunk of the car, it determines how much load you can carry/store
6. The videocard is the windscreen and wipers of the car, the bigger they are the more details you see in gaming
7. The PSU is the petrol-tank of the car, use a too small one and your machine stops way before reaching your target.

Maybe now you have a clue that you are on the wrong track?
Sadly people don't do their homework before buying stuff, as such they do not know what they are buying and end up frustrated because they think something is wrong.

Ram is just 1 component....there is also more to a car then just a tire. :rolleyes_anim:

No, actually I think I am pretty much on the right track.  Yes the memory controller on the CPU is 1333.  But if you read the OP, you can see that what he describes (and what I found out) is that the chips on our RAM are actually 1033, 1333, and sometimes 1600 chips, overclocked from the factory to the speeds you buy and pay for ("What this tells us is that these are DDR-1333 modules overclocked to DDR-2133 and programmed with an XMP profile to support that without manual adjustment.  The actual speed of the module is DDR-1333, but the manufacturer's rated speed is DDR-2133.  Like I said previously, manufacturer's rated speeds require at least entering the BIOS and either; enabling XMP, or manually configuring timings, voltage and speed.").  Therefore, this can cause instability with the system, I believe if the chips on the RAM were actually at the speeds advertized (1600, 1866, 2133), we would have a much greater chance (of course not 100% guaranteed because of the CPU) of running at those speeds.  If the CPU was strictly what is limiting the RAM, wouldn't EVERYBODY on a Sandy Bridge system not be able to get their RAM up to 2133, because I AM seeing plenty people do you.  The CPU may be ONE factor, but the RAM not having the chips on board at advertized speeds is another factor.

As for the lawsuit, seriously...  I was just venting, it was more of a rhetorical statement, being angry about the RAM issue.  If you have a problem with the post, please delete it.  

 

[Jack the Newbie]

The CPU may be ONE factor, but the RAM not having the chips on board at advertized speeds is another factor.

Yes, whenever stability issues occur, one has to check both the memory controller specifications and the memory module specs (if true specs are available). However, whereas CPU/memory controller specifications are pretty straight forward and pretty easy to check, differentiating between "true" specs and "OC specs"/"advertised specs" when it comes to memory modules, really has become a blurry business.

 

[doubleohseven]

differentiating between "true" specs and "OC specs"/"advertised specs" when it comes to memory modules, really has become a blurry business.

Agreed.  I wish I would have known what I know now, BEFORE I bought two different kits of RAM, then I would have checked for the true speeds.  But the way they market RAM, they make it seem that you are buying RAM at that speed, leaving no reason to believe otherwise.

 

[Jack the Newbie]

they make it seem that you are buying RAM at that speed, leaving no reason to believe otherwise.

As I keep pointing out:  check the voltage recommendations that come with the advertised frequency/timing ratings! DDR3 industry standard voltage as defined by JEDEC is and always was 1.5V +/-0.075V.  As soon as you see voltage recommendations that exceed these voltage specifications you can pretty much be sure that the advertised ratings are non-standard.  No memory chip(!) manufacturer really produces anything that does not meet the specs. 

Here are links to (DDR3 SDRAM chips) parts lists of major memory (chip) manufacturers:

Micron: http://www.micron.com/partscatalog.html?categoryPath=products/parametric/DRAM/ddr3_SDRAM
Elpida: http://www.elpida.com/en/products/ddr3.html
Hynix: http://www.hynix.com/inc/pdfDownload.jsp?path=/upload/products/gl/products/dram/down/DDR3.pdf
Samsung: http://www.samsung.com/global/business/semiconductor/productList.do?fmly_id=691&xFmly_id=690

Check the specs and then look at current advertised memory ratings.  Go figure.

 

[HU16E]

So when you plug your memory into your computer and boot it up for the first time, do not expect 1600+ speeds the first time around.  You'll at least have to enable XMP/EPP and/or manually configure (timing and voltage) settings in the BIOS.

Well Aaron, it looks like the situation has changed a bit with the introduction of the new Hyper PnP memory from Kingston for P67 & Z68. Looks like they took RAM manufacturing to the next level for Sandy Bridge & came up with some SPD profile programming of the chips that really works. PnP of 1600 or 1866 RAM speeds with 'NO', yes, you are reading this right, no manual tweaking in the BIOS required, '&', no having to set X.M.P. or the need for a custom revision in a special BIOS release! Now that's innovation! Without naming a specific brand of RAM, to get them to work correctly (in some cases), we shouldn't have to be forced to use X.M.P. or a special BIOS to get them to work right. Looks like Kingston took the bull by the horns & came up with an ultimate 'no fiddling around' plug 'n' play solution for those so inclined to believe these faster RAM speeds have much benefit with Sandy Bridge in the first place. It's all still kind of comical in regards to any significant practical gains associated with RAM speeds over the platforms 1333. With Sandy Bridge, the RAM speed seems to be the bottom of the performance food chain. CPU speed & the quality of the VGA(s) provide the biggest impact.  

Disclaimer at the Kingston Website;

"Notice: All Kingston products are tested to meet our published specifications. Some system or motherboard configurations may not operate at the published HyperX memory speeds and timing settings. Kingston does not recommend that any user attempt to run their computers faster than the published speed. Overclocking or modifying your system timing may result in damage to computer components".

A hat tip to Kingston! They tell it like it is right up front!

Added: This reply in Aaron's thread isn't any kind of endorsement for a specific product brand, just an FYI!

 

[MarkedOne]

Good new 16e...  Kingston is not a new player in town, as far I remember they were there. I'm not surprise it's them who bring PnP memory to Sandy. They have a huge part of the servers market, so they know how to develop reliable memory.

 

[Sach]

Thanks guys. 

 

[CyberWarrior]

Ok from what I have read so far,I should thank my lucky stars that my RAM is running at 1866mhz instead of
the rated 2133mhz,which would be too much to ask

 

[HU16E]

Ok from what I have read so far,I should thank my lucky stars that my RAM is running at 1866mhz instead of
the rated 2133mhz,which would be too much to ask

A lot depends on the quality of the modules, but most of the burden is on the CPU IMC.

 

[badboy2k]

the Memory Controller on your CPU is always the biggest factor to what speed you RAM will actually work at and is the Most common Problem that causes Memory to run bellow specs as it can't handle it!

usually i always get RAM thats rated 1 level higher then i plan to use it at just for stability so they run at a lower stress level EG: if i want 2100MHz i will buy 2400MHz DIMMS but your still held back by the IMC on your CPU...