The Most Common DDR DRAM Myths Debunked

All DDR Is The Same

In Part 1, we examined some basic facts about DRAM. Now, we’ll look at some topics that are often more contentious. Here's what we’ll cover in Part 2:

  1. All DDR3 Is The Same
  2. Just Add More DRAM
  3. There Are Only A Few DIMM Manufacturers
  4. 3200 MT/s Support Means You Can Use Any DRAM
  5. Mixed DRAM Runs At The Speed (Or Timings) Of The Slowest DIMM
  6. It’s Cheaper To Buy Two Sets Of DIMMs Than Larger, More Expensive Sets
  7. DRAM Will Run Faster With All Slots Filled
  8. There Are No Performance Gains With DRAM Faster Than 1600 MT/s
  9. 8GB Is All You'll Need For The Next X Years
  10. You’ll Never Use Or Need 16GB Or More
  11. I’m Not Using All My DRAM, So More DRAM Won’t Increase Speed
  12. A 64-bit OS Lets You Run All The DRAM You Want
  13. 1.65 Volt DRAM Will Damage Your Intel CPU
  14. Dual-Channel Mode Doubles The Data Rate, Or Is Twice As Fast

All DDR3 Is The Same

This topic alone could take up a lot of space, but I will try to keep it short and offer some suggestions. Here are a few examples:

  1. I’ve mentioned Kingston’s line of Fury DRAM, which doesn't come with an XMP profile but instead operates using plug and play. They look nice, come in a variety of heat sink colors, are reasonably priced and appeal to people with older systems who want to upgrade their DRAM. But since they are based off PnP, they will operate only under various motherboard chipsets: H67, P67, Z68, Z77, Z87 and H61 from Intel, along with AMD's A75, A87, A88, A89, A78 and E35. You can include Z87 and Z97. The sets I listed are direct from the company’s product page.
  2. The actual chips also differ:
    • Most of the DRAM being manufactured today uses high-density, 4Gb memory chips, whereas older DDR3 used lower-density 2Gb chips. Older memory controllers are often limited to lower densities. One of our editors recently found that none of his P55 motherboards worked with any of his 8GB modules, and if modules with different densities are mixed, a module can become undetected or unstable.
    • There is a number of different companies that make memory chips, and they make them to their own specifications. They also make multiple models of each chip. Each of those lines is split up or binned according to the strength of the chip.
  3. Most enthusiast-oriented motherboards are designed to take non-error-correcting coding (ECC), unbuffered DRAM. Usually, ECC is for servers and professional workstations where data integrity is critical, and buffered (registered) DIMMs are used exclusively in servers that require ultra-high memory capacity. Sharing technology among high-end platforms allows some enthusiasts to have the option of using ECC on their motherboards.
  4. There are other examples covered elsewhere, like DRAM with a data rate that’s too high for your CPU (but still functions at a slower default data rate).

Usually, I suggest checking with the DRAM manufacturers, which spend a lot of time testing their memory on the various motherboards out there. The motherboard manufacturers provide a qualified vendors list (QVL) of the DRAM they have tested with a given product, but it usually consists only of the small variety of DRAM they have available in their labs and isn’t as reliable as checking directly with the DRAM manufacturers. In the Tom's Hardware forums, I have found many rather knowledgeable members who provide good advice on various DRAM for specific motherboards and platforms, as well as information about what data rates the different CPUs can handle.

Just Add More DRAM

JEDEC is a council of electronic-device manufacturers and design firms that sets industry standards to be universally adapted by its members. Because some DRAM manufacturers decided to exceed the JEDEC maximum DDR3-1600 CAS 11 (and, later, CAS 9) by offering tighter timings and higher data rates, mixing DRAM has not been as easy as the council intended.

Simply put, mixing DRAM from different packages is a crapshoot, even when you have two identical packages of the same exact DRAM model. I would like to add that DIMMs that don’t appear to work well together often, but not always, can be helped with voltage and/or timing adjustments. There are a couple of examples in "DDR3 Memory: What Makes Performance Better?" where two of the companies didn’t market 32GB sets of 2400 MT/s DRAM and sent me a pair of matching 2 x 8GB sets. Neither worked initially, and it took minor adjustments for them to run smoothly.

Why is this such a problem? After all, they are the same frequency, timings and voltage.

DRAM is made up (basically) of memory chips that are soldered to a PCB (printed circuit board), driven by electricity. During the course of a DRAM production run on a given model, the manufacturer might be finishing up a large section of PCB that has been cut to the DIMM size but then might switch to a new PCB from a different production lot, which can result in slightly different properties.

The same can happen with the physical solder; the manufacturer may change to a completely different kind that has ever so slightly different conductivity properties. 

Then, there are the dies themselves. When made by the actual chip manufacturer, the chips are "binned" (sorted) according to their quality.

Let’s take a closer theoretical look at this concept. A single production lot may result in, say, 1000 memory chips, which are separated or binned. A manufacturer may classify 200 chips as entry-level, and separate 350 chips that are a little better, 300 chips that are even better and 150 chips that are the best. Then, they sell these chips to different manufacturers.

If you were to go out and buy an 1866 MT/s module from each company, you would likely be getting a different PCB in each, a different solder with various conducting qualities and quite possibly differently graded chips and/or chips from different manufacturers.

Several companies are making memory chips, which further adds to the questions about compatibility, and you might start to see why mixing DRAM can be, and often is, problematic.

We also noted earlier that most newer lines of DRAM use 4Gb densities, whereas the norm with older lines was 2Gb.

There Are Only A Few DIMM Manufacturers

This is both myth and misrepresentation. There are a number of companies that make memory chips and numerous companies that make DRAM modules. There is rebranded DRAM out there made by one or more companies for other companies. For instance, the AMD Radeon lines of DRAM are made by Patriot and VisionTek.

3200 MT/s Support Means You Can Use Any DRAM

To run pricey 3200 MT/s memory, you also need a CPU that can handle such a high data rate. Otherwise, your DRAM may only run at 1333, 1600 or 1866 MT/s, at best. 

In the days of Intel’s LGA 775, CPU and DRAM overclocking was controlled primarily by the FSB (front-side bus). Let’s say you had a Q6600, and your motherboard supported a 1066MHz FSB. Left there, your CPU would run at its native 2.4GHz and your DRAM at 1066 MT/s. If you were to overclock the CPU by raising the FSB to 1333, your CPU would run at 3GHz and you could run DRAM at 1333 MT/s. In other words, the memory was limited to the FSB's ceiling. The memory controller (MC) was in the chipset—most often, the motherboard's northbridge—and ran at FSB frequency.

Now, the MC is in the CPU. So, if you want to run at your memory's advertised specs, the CPU is the primary factor. Haswell-based CPUs are rated at 1600 MT/s DRAM, and mid- to upper-tier non-K CPUs can typically run 1866 up to 2133 MT/s fairly reliably. For higher data rate DRAM, a “K” model CPU can be overclocked, thus helping the MC support more enthusiast-oriented modules.

AMD’s current FX CPU line is rated at “up to 1866 MT/s at one DIMM per channel.” However, you may find yourself running into problems with lower-end CPUs—and, at times, even the higher-end CPUs—running 1866 MT/s. This is partly because the MC in the FX CPUs is optimized for DDR3-1333 (according to the BIOS and Kernel Programming Guide). As with any CPU, FX CPUs can be overclocked to run even higher than DDR3-1866, but mileage will vary.

Mixed DRAM Runs At The Speed (Or Timings) Of The Slowest DIMM

Let’s say you have a DDR3-1600 CAS 9 DRAM module and you add one rated at 1866 CAS 9. One outcome is that the DRAM will go to the motherboard’s default of 1333 CAS 9 or 10 (or, many AMD motherboards default to 1066). Or, both will run at 1600 CAS 9 (or 10 or even 11) if DOCP, EOCP, XMP or AMP was enabled before you added the 1866 MT/s module.

But you can also manually set them to something else. Typically, in a scenario like this, I’d try 1866 at 10-10-10-27. Add a pinch of voltage to the DRAM (e.g., +0.005V). Depending on the results, you can also tune the MC voltage.

It’s Cheaper To Buy Two Sets Of DIMMs Than Larger, More Expensive Sets

Even though you are buying two of the exact same sets, there is no guarantee that they will work together. The DRAM that goes into a package has been tested to work together. Manufacturers don’t guarantee mixing or adding one set to another, even when they are the same exact model.

Customers often try this with higher data rate sticks using XMP to set them up.  With XMP enabled, the motherboard may read the profile for two sticks of DRAM and set the secondary timings accordingly, but the tRFC timing for two modules may be 226, whereas four sticks require 314.  This can be especially hard for most users to troubleshoot/find, as few ever go into the secondary DRAM timings.

DRAM Will Run Faster With All Slots Filled

Running two sticks of DRAM puts less stress on the memory controller than four. Less electricity is needed, the memory controller needs less voltage to remain stable and, while it isn’t noticeable, the DRAM runs ever so slightly quicker (generally). The same holds true for tri- and quad-channel motherboards. Part of the misconception is that four DIMMs (often sold as a quad-channel set) will always run in full quad-channel mode, even though a dual-channel motherboard doesn’t support this feature.

There Are No Performance Gains With DRAM Faster Than 1600 MT/s

The answer to this depends on many factors. It is completely false if you are using a CPU's or APU’s on-board graphics. They use your system DRAM—and the faster, the better!

Most DRAM benchmarks measure read, write and copy performance. Many gaming benchmarks demonstrate a 3 to 5 FPS gain on DRAM between 1600 and 2133 MT/s. That’s because, in most games, DRAM is used primarily as a pipeline to feed information to the GPU and as a holding area for frequently retrieved data. The fact remains that it can increase FPS a little. Because the price of DRAM between 1600 and 2133 MT/s is only narrowly differentiated, it can sometimes still make sense to get the higher data rate DRAM.

Furthermore, the file compression program WinRAR pulls the data into DRAM and compresses it to DRAM before writing it back to the drive. Benchmarks using WinRAR can show a 25-percent gain going from 1600 MT/s to 2400. And there are plenty of other memory-intensive applications: editing video, working with images, CAD, running VMs and so on. While some of the gains might be small, the little snippets of savings add up if you use those applications.

If you are doing one task at a time—writing a memo, then browsing a Web page and then watching a video—you don’t really need faster DRAM. If you multitask, however—for instance, if you have a bunch of browser tabs open while you're working on a good-size spreadsheet, or if you're running video in a window, are working with images and maybe running a virus or malware scan in the background—then the faster memory can be far more beneficial.

You can test this out by running some applications like these with 1600 MT/s DRAM and then something faster. Once you’ve loaded up your system with several programs, use something like the SiSoftware Sandra system benchmark, and then use WinRAR on a large file. While it runs, hop around through your open Windows, and then check your scores in Sandra and the elapsed time for the WinRAR.

8GB Is All You'll Need For The Next X Years

If you don’t really multi-task, then 8GB is fine. But that isn't the case for gamers and enthusiasts. Five years ago, 2GB was thought to be enough, then 4GB and so on.

Another signal: computer vendors are typically stingy with DRAM, so when 2GB seemed like enough, they were providing 1GB, for example. Today, 6 to 8GB is the norm, and 16GB isn’t uncommon, suggesting that 8GB isn’t going to be enough for long. Games are using more DRAM. If you want to keep a rig for more than a year or two, I suggest a 16GB entry point.

You’ll Never Use Or Need 16GB Or More

This continues with the theme from Myth 9, but it's geared more to those heavy multi-taskers and users of memory-intensive software, or those who work with large data sets and files. The more DRAM you have, the more data it can hold for recurring instant access rather than having to go back to the page file on the hard drive or back to the Web to reread the data.

Many people use more than 20GB at a time almost every day, and this is also becoming the norm among those in the Tom’s Hardware forums, with members talking about maxing their 8 and 16GB kits.

Remember, too, that manufacturers are doing a ton of research and outreach to other manufacturers, software developers and users, so there are definitely reasons why motherboards are being designed to run 32GB, 64GB and 128GB (or more) of DRAM. 

I’m Not Using All My DRAM, So More DRAM Won’t Increase Speed

While more DRAM might not speed things up, in most instances, it certainly can. Many programs adjust the amount of data stored in RAM as a percentage of RAM available, so having more DRAM saves time by holding more oft-used data in RAM (rather than on the hard drive). This can be particularly beneficial when you're working on projects with multiple images or video, CAD, GIS, VMs, etc. Another benefit of having lots of DRAM is the ability to create a RAM drive for loading games, other applications or data sets. Doing so can have its pitfalls, but many swear by it.

A 64-bit OS Lets You Run All The DRAM You Want

Many people believe that, with a 64-bit OS, you can use an unlimited amount of DRAM, which isn’t true. Here are the DRAM limitations for Windows 7, for example:

Windows 7 DRAM Limits


x86 (32-bit)x64 (64-bit)
Windows 7 Ultimate4GB192GB
Windows 7 Enterprise4GB192GB
Windows 7 Professional4GB192GB
Windows 7 Home Premium4GB16GB
Windows 7 Home Basic4GB8GB
Windows 7 Starter2GBN/A

And on Windows 8:

Windows 8 DRAM Limits


x86 (32-bit)x64 (64-bit)
Windows 8 Enterprise4GB512GB
Windows 8 Professional4GB512GB
Windows 84GB128GB

1.65 Volt DRAM Will Damage Your Intel CPU

Intel recommends 1.50V for DRAM at the CPU’s specified data rate. On Haswell, that’s DDR3-1600 DRAM. But even that is a bit misleading, as Intel certifies DRAM (even DDR3-1600) that runs at 1.60 and 1.65 volts. Keep in mind that 1.60 to 1.65 volts is considered the norm for DRAM at 2133 MT/s and higher data rates.

The majority of the DRAM available in lower data rates (like DDR3-1333 and 1600) is 1.50V or less. I suggest people stay away from those data rates when voltages are 1.65, as this can mean the manufacturer used marginal memory chips. Why would DRAM with decent chips even need 1.60 to 1.65V? I generally take it a step further and stay away from 1866 MT/s DRAM that exceeds 1.50V, unless it is higher-performance (CL7 or CL8).

Dual-Channel Mode Doubles The Data Rate, Or Is Twice As Fast

This is another misconception. The DRAM itself is DDR (double data rate), so it runs at double the clock frequency (800MHz DRAM has a 1600 MT/s data rate). When you put two DIMMs in dual-channel mode, the DRAM goes from operating as an individual 64-bit device to working together and being seen by the MC as a single 128-bit device. Theoretically, that would double the bandwidth, but in actuality, it provides a performance boost of only 20 to 50 percent on Intel CPUs, and a little less on AMD rigs.

I’ve written this with input from many Tom's Hardware forum members—too many to mention individually. I’d also like to thank the fine people at Corsair, G.Skill and Team Group, whose DRAM expertise and willingness to share it are much appreciated.

As always, comments, criticism and critiques are welcome.

MORE: Best Memory
MORE: Memory in the Forums

Jim Reece is a Contributing Editor for Tom's Hardware, covering Memory.

Follow Tom's Hardware on Twitter, Facebook and Google+.

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  • damric
    Well that was a good read. Thanks Tradesman!
    21
  • Other Comments
  • damric
    Well that was a good read. Thanks Tradesman!
    21
  • Nuckles_56
    Thanks for the article, I've been impatiently waiting for it since the first one
    4
  • JackNaylorPE
    Some if these could use a bit more detail.

    "All DDR3 is the same" ... Just wanted to mention that in close on 25 years managing and participating in web forums, can't say I have ever seen this one put forth for either DDR3 or anything else. There are numerous differences, some matter not at all, some matter a little, some can matter a lot. It's crapshoot, but the odds are pretty good if you don't have a lot or large differences.

    "Mixed DRAM Runs At The Speed (Or Timings) Of The Slowest DIMM" - I think this is just poor wording of the intent when this one is used. More correctly, it's much like video cards .... one card is advertised and guaranteed to run at one speed, the other a little bit faster. Like RAM, in SLI / CF you have a pretty good likelihood of setting them up to run at the lower of the two speeds. You have a lesser change of getting them both to run at the higher speed, tjo it's worth trying; that slower advertised card may have some headroom that was previously untapped

    You also have the issue that 2 cards put more of a strain on the PSU and when that extra load is present, voltage stability suffers. Your faster card, with more voltage variation may not be able to handle the same OC that you had before the 2nd card's load was added.

    Same w/ RAM ... one would presume that if a set of RAM was capable of a higher speed, it would have been binned and sold at the higher speed. As vendors respond to the variability of supply and demand, we may see better quality sets sold at lower rated speeds, which we can attest to by reading how many reviews in which the tester was able to get significantly higher speeds. So when someone says "will run", I have always taken it to mean "the likelihood is that it will be able to run at the less demanding of the two speeds / timings. As always, no guarantee. As it is, your likelihood of getting 2 1600 sets to work together is much higher than getting two 2400 sets to do the same. Success will be better at 1600 / 1600 and 1333 / 1600 than it will be at 2400 / 24500 or 2400 / 2666

    I haven't been asked to do many upgrades since Sandy Bridge days (when some folks were still buying 2 x 4GB) but back then at 1333 / 1600 and 1600 / 1600 matchups, our success rate was well over 90%. And those difficulties came usually resulted from having different module OEMs. In the last 3 years, I'd say 9/10 builds started with 16GB and those who chose 8GB are still content, so don't get the opportunity any more.

    "Just add more DRAM" .... I'd add that the most common cause if mismatch results from the maturation process of the production lines.... When DDR3 first broke 1333 was the most commonly purchased speed, as productions lines matured and yields improved this grew to 1600 and of late we have seen great yields on 1866, 2133 and now even 2400. As lines mature and yields improve, required voltage also comes down.

    Initially, a vendor will usually buy their lower speed modules from one vendor and then sign on with a higher quality vendor to fill their needs for higher speed RAM. Over time, the lower price vendor's yields may be sufficient to supply their demand for the higher speeds. So we wind up with a situation where a vendor's product from 2012 will use one brand of module and one from 2015 will be from another. That presents quite a challenge for compatibility.

    This can be particularly frustrating as one version from January 2012 and one from November 2014 might work fine and then one from November 2014 and January 2015 might have no chance in "H E double sticks" even tho every one of them has the exact same model number. Sometimes you can notice this by a slight change in timings. Several vendors offered 2400 at one time at 10-12-12-28, nor those same models are 10-12-12-30 or 10-12-12-31.

    "It’s Cheaper To Buy Two Sets Of DIMMs Than Larger, More Expensive Sets" That's not a myth, at least not as stated.... they are cheaper. The "myth" as stated doesn't say anything about working :). They may not run together at advertised speed but they are still cheaper.

    "There Are Only A Few DIMM Manufacturers" .... given the limited 2 sentence attention this subject got, the topic should have been eliminated.
    -1
  • djsvetljo
    Wait a second, I thought boards like Z97 have their own Memory Controller, separated from the CPU and 2400Mhz RAM is usually not a problem with Z97, am I right?
    -1
  • TechyInAZ
    As always, thank you Tradesman! Such a big help.

    Quote:
    Wait a second, I thought boards like Z97 have their own Memory Controller, separated from the CPU and 2400Mhz RAM is usually not a problem with Z97, am I right?


    Nope, CPUs have the MC in the CPU itself. It's faster since it's directly in the CPU which also saves energy compared to the old way of storing it on the mobo.

    I personally run 2400mhz on a Z97-A with a i5 4690K and I've had no issues.
    2
  • Dark Falz
    There were instances with past chipsets where 4 DIMMs would be faster than two, due to the way the chipset interleaved memory or leveraged reads. This was true of my Pentium 4 system (yes, I realise how old it is). Probably stopped with the IMC. I picked up a second 8 GB kit from eBay a few years after putting my IB together and lucked out, despite a few months difference in mfg date they work perfectly with the existing kit and appear to the same package/chips. They run at 1.50v too when they are rated at 1.65v. TBH I haven't yet seen any benefit from 16 GB vs 8 GB for anything I run, but I mostly just run games and Chrome. I suppose there's 8 GB more for Windows caching but that's less important with SSDs and modern streaming engines.
    1
  • Tradesman1
    Anonymous said:
    Well that was a good read. Thanks Tradesman!


    ____________________

    Appreciate it ;)
    1
  • Tradesman1
    Anonymous said:
    Thanks for the article, I've been impatiently waiting for it since the first one

    _____________________________

    Thanx, have had a number of PMs and emails about when this would be published, it's been been done and waiting ;) I will say, the staff at Toms is small and they are are no doubt overwhelmed with the number of pieces that they publish. Hopefully it will be of help to many

    T
    0
  • Tradesman1
    JackNaylorPE

    Comment - “Some if these could use a bit more detail.”

    Always and forever true. In this particular piece, many items had more detail, examples and explanations as written. However I have no say as what they do with the piece once accepted. Originally it was one piece, with a working title of “DDR3 – FAQs and Fiction”, (have no idea where they came up with adding “and Troubleshooting Guide”, a guide to troubleshooting would be a step by step thing).

    Comment - “All DDR3 is the same”

    In the first piece introduction I stated “purpose of this article is to address the most commonly asked questions we hear, and to debunk some of the myths” - The “all DDR3 is the same” is a comment seen daily in the memory area of the forums, and as with the other is a myth, as I mention, this subject alone could be the basis for an article (as could others)
    Comment – “Mixed DRAM Runs At The Speed (Or Timings) Of The Slowest DIMM"
    Again this is a common misconception that is seen daily, and thus was included and explained.

    Comment - "Just add more DRAM"

    First, with the intro of DDR3, back with the 775 and 1366 mobos 1066 was the prominent data rate being sold, 1333 and 1600 were considered the ‘enthusiast’ data rates of choice. The 1366 CPUs were rate 800-1066. The early 1156 Pentiums and Celeron CPUs were rated 1066 and then the Clarkesdale and Lynfield i3-i5-i7 CPUs were rated to 1333. (Also keep in mind, the original JEDEC specs for DDR3 only went up to 1600 which was the max data rate).

    This Item in particular was much larger and had an example of of a vendor making a model of a chip, binning it to different levels, selling them to different manufacturers who further binned them, etc, etc.. That part wart was sliced and diced ;) Here you talk of chips produced years apart and seem to miss the point that you can sticks of DRAM right off an assembly line and they might play nice, they might not. This is why manufacturers test DRAM that goes into a package

    Comment – “It’s Cheaper To Buy Two Sets Of DIMMs Than Larger, More Expensive Sets"

    Keep in mind that this article was aimed at statements often see/heard coming from others giving ‘advice’ propagated by ‘experts’ and stated as a fact to those who are looking for 4 sticks for a single rig.

    Originally I phrased it as “Just buy 2 sets of two DIMMs rather than those more expensive 4 DIMM sets, it’s cheaper”, to try and keep the title short. The statement/advice is true based on the idea that ‘generally’ (not always) the initial costs is lower as a pair of 2 stick sets, is normally cheaper than a 4 stick package, but in fact if they don’t play, you face return mailing fees or travel and your time, restocking fees, the fact that the store may not offer refunds, downtime from not having DRAM, etc

    Comment – “There Are Only A Few DIMM Manufacturers”

    Once again an item that was not presented as written, my line title for this, was that all too often heard “There are only a couple of companies that make DIMMS; then they all get rebranded”. My explanation may make better sense when read as an answer to my title (where I had it as ‘a couple’ rather than the editorial privilege taken by Toms to change it to say ‘a few’) . There are many that believe (mistakenly) that there are only couple of companies that manufacture DRAM and then put their name on them (rebrand).

    I appreciate the comments (and have a feeling I’ll be explaining some of these over and over, as well as others ;) )
    1
  • Memnarchon
    Great article, It was a good read indeed.
    Just 1 thing.
    For "13. 1.65 Volt DRAM Will Damage Your Intel CPU", I had a personal experience with previous generation DDR2 with overvloted RAM.
    Back then (with a Kentsfield CPU) as you said the MC was in Northbridge. It was fine for many years running at the rated voltage over the normal DDR2 suggestion (I think the normal was 1,8V).
    But one day after 6 years working fine, the MC from the motherboard died. The techguy that diagnosed the problem, said that this happened from years of overvolting RAM.
    My dead $200 mobo suggests that this might not be a myth afterall. :P
    But in the end this might be a problem that is left behind with DDR2 or Glenwood/Lakeport/Broadwater...
    0
  • Tradesman1
    Anonymous said:
    As always, thank you Tradesman! Such a big help.

    Quote:
    Wait a second, I thought boards like Z97 have their own Memory Controller, separated from the CPU and 2400Mhz RAM is usually not a problem with Z97, am I right?


    Nope, CPUs have the MC in the CPU itself. It's faster since it's directly in the CPU which also saves energy compared to the old way of storing it on the mobo.

    I personally run 2400mhz on a Z97-A with a i5 4690K and I've had no issues.

    ______________________________________

    djsvetljo

    Think TechyinAZ covered that ;) The MC (memory controller) on the mobo, went to the wayside with the demise of the socket 775 mobos about 6 years. And yes, the 4790K should have no trouble w/ 2400 sticks, depending on the individual 4790K it may reuire a slight OC of the CPU

    TechyinAZ

    Thanx for jumping in and the comments, just found this published today via some PMs and emails ;)
    1
  • Tradesman1
    Anonymous said:
    There were instances with past chipsets where 4 DIMMs would be faster than two, due to the way the chipset interleaved memory or leveraged reads. This was true of my Pentium 4 system (yes, I realise how old it is). Probably stopped with the IMC. I picked up a second 8 GB kit from eBay a few years after putting my IB together and lucked out, despite a few months difference in mfg date they work perfectly with the existing kit and appear to the same package/chips. They run at 1.50v too when they are rated at 1.65v. TBH I haven't yet seen any benefit from 16 GB vs 8 GB for anything I run, but I mostly just run games and Chrome. I suppose there's 8 GB more for Windows caching but that's less important with SSDs and modern streaming engines.

    ----------------------------------------

    Thanx for the response,

    Yes, I ran into that with some older rigs also, and it can be true even today. This article had a working title of "DDR3 - FAQs and Fiction" and is aimed at todays DDR3 rather than the broader spectrum of simply DDR as Toms has entitled it, which to many will encompass the original DDR, DDR2 and even DDR4, which isn't how it was meant.
    0
  • Tradesman1
    Anonymous said:
    Great article, It was a good read indeed.
    Just 1 thing.
    For "13. 1.65 Volt DRAM Will Damage Your Intel CPU", I had a personal experience with previous generation DDR2 with overvloted RAM.
    Back then (with a Kentsfield CPU) as you said the MC was in Northbridge. It was fine for many years running at the rated voltage over the normal DDR2 suggestion (I think the normal was 1,8V).
    But one day after 6 years working fine, the MC from the motherboard died. The techguy that diagnosed the problem, said that this happened from years of overvolting RAM.
    My dead $200 mobo suggests that this might not be a myth afterall. :P
    But in the end this might be a problem that is left behind with DDR2 or Glenwood/Lakeport/Broadwater...

    _____________________________

    Couple of things, The title given to this article is rather deceptive. My title for the article was simply "DDR3 - FAQs and Fiction" (Part 1 and Part 2), which to me was short,sweet and to the point, Toms decided to change and make individual titles to the two parts, in the first they added something about "and Troubleshooting Guide" which isn't the intent of the article - the intent was simply to look at FAQs (Frequently Asked Questions) and Fiction (to include Myths and Misrepresentations about DDR3 that are often heard). In this second part they call it, in part "Common DDR DRAM" which isn't accurate as that encompasses DDR, DDR2 and DDR4 which are different animals so to speak.

    I don't know the circumstances of the failure you encountered, but have encountered those types of problems with DDR2 also, the MC (memory controller) was generally based within the NB chipset on Intel 775 and earlier mobos. That chipset was also running more than just the MC, primarily FSB, which would also OC the CPU and the rest of the rig, that in part was one thing that led to Intel moving the MC to the CPU
    1
  • Doug Lord
    Can you comment on quad channel vs dual? Of you had a x99 board would you go 4x4 for quad, or 2x8 for future upgrades?
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  • Tradesman1
    I always recommend getting the full amount of DRAM you want/need in a single package. I'm not a proponent of mixing sets of DRAM, as in adding DRAM to existing, as there is no guarantee the new will play with the old, which can lead to frustration, mailing/return fees, restocking fees and not having the DRAM when you want/need it if the new and old don't want to play. With a X99 I would go 16, 32 or 64GB in a 4x config to fully utilize the quad channel capabilities of the rig. While the article has had a title given to it by TomsHardware (my working title was "DDR3 - FAQs and Fiction") here in this second part they call it in part "Common DDR DRAM" which tends to imply DDR, DDR2 and DDR4 also, which wasn't intended (by me anyway). Have already seen where some are buying couple of sets of 2x or 4x packaged sets and having problems on X99
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  • g-unit1111
    Anonymous said:

    "There Are Only A Few DIMM Manufacturers" .... given the limited 2 sentence attention this subject got, the topic should have been eliminated.


    Can you elaborate on this one a bit more? Are you talking like the actual manufacturers that really assemble the DRAM or are we talking OEMs like Corsair that resell that already manufactured RAM?
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  • tsnor
    "Many people use more than 20GB at a time almost every day"

    It's VERY rare to find a system where the windows pagefile size plus the total of memory approaches 20GB. The default page file size on my win7 system with 8GB of memory is 4GB, so the total backing space I have for virtual memory is only 12GB. My system cannot hit 20GB.
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  • jshoop
    I don't know about others, but i always said "all ddr3 is the same" meaning it doesnt matter what kit you get, if there are 2 kits with the same timings and speed ratings, get the cheaper one. They will perform basically the same. The myth brings up a misconception i never thought about, i hope i wasnt confusing people and spreading the rumor :)

    either way, this was a good read. i like the work tradesman!
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  • Tradesman1
    Anonymous said:
    "Many people use more than 20GB at a time almost every day"

    It's VERY rare to find a system where the windows pagefile size plus the total of memory approaches 20GB. The default page file size on my win7 system with 8GB of memory is 4GB, so the total backing space I have for virtual memory is only 12GB. My system cannot hit 20GB.

    _______________________

    ;) I think you'd be surprised at how may people will exceed 20GB at a given time, granted people doing single operations at a time aren't going to, but these days muti-tasking is more the norm, people are running VMs even on lower end rigs, video editing is common place. There's obviously many that do and it's accepted by the marketing people, last I looked the Egg was offering over 200+ 32GB sets in 4x8GB alone (and if you want to include DRAM + page file, they have over 700 16GB offerings....and 64GB offering continue to grow, there is now 128GB sets available and soon to be available
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  • Tradesman1
    Anonymous said:
    I don't know about others, but i always said "all ddr3 is the same" meaning it doesnt matter what kit you get, if there are 2 kits with the same timings and speed ratings, get the cheaper one. They will perform basically the same. The myth brings up a misconception i never thought about, i hope i wasnt confusing people and spreading the rumor :)

    either way, this was a good read. i like the work tradesman!


    ___________________

    Thanks, I enjoyed writing this (in large part to help in the forums, now I can pop in a link to a part of this rather than have to typr out the same things over and over), but as I mentioned in the opening of Part 1, DRAM may well be the least understood component in a rig. The title that they stuck on this Part 2 is somewhat deceptive stating 'DDR' instead of 'DDR3', as DDR3 has gone through much more evolution wise than did DDR or DDR2 where the manufacturers stuck more to JEDEC standards and suppliers of chips and all were more limited.
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