Puget Systems print logo

https://www.pugetsystems.com

Read this article at https://www.pugetsystems.com/guides/520
Article Thumbnail

Advantages of ECC Memory

Written on November 5, 2013 by Matt Bach
Share:

What is ECC?

ECC (which stands for Error Correction Code) RAM is very popular in servers or other systems with high-value data as it protects against data corruption by automatically detecting and correcting memory errors. Standard RAM uses banks of eight memory chips in which data is stored and provided to the CPU on demand. ECC RAM is different as it has an additional memory chip which acts as both error detection and correction for the other eight RAM chips.

Prior to ECC memory, error detection was done via even or odd parity bits. In a computer, data is most commonly stored 8-bit chunks. When parity is being used, an additional ninth bit - or parity bit - is written which allows the system to detect when there is an error. If the system uses even parity, then the 1's and 0's (including the additional parity bit) should add up to an even number. For example, if the data written to the RAM is "10011011", since even parity is being used, a 1 would be added to the data so that when you add up the numbers (1+0+0+1+1+0+1+1+1), you get an even number. If an error were to occur and the data the RAM sends to the system is instead "10011001+1" (which adds up to an odd number), then the system knows that the data is corrupt.

ECC is an extension to parity as it uses multiple parity bits assigned to larger chunks of data to not only detect single bit errors, but correct them automatically as well. Instead of a single parity bit for every 8 bits of data, ECC uses a 7 bit code that is automatically generated for every 64 bits of data that is stored in the RAM. When the 64 bits of data is read by the system, a second 7 bit code is generated, then compared to the original 7 bit code. If the codes match, then the data is free of errors. If the codes do not match, the system can determine where the error is and fix it by comparing the two 7 bit codes.

The method of comparing the two codes is most commonly done by what is called the Reed-Solomon code. Warning, only attempt to understand the Reed-Solomon code if you really, really like math.

What about Registered Memory?

Registered (often referred to as "buffered") memory uses a technology that is often paired with, but not directly related to, ECC RAM. Registered memory has a "register" that resides between the RAM and the system's memory controller which lessens the load that is placed on the memory controller itself. This allows for more memory modules to be used at one time than would otherwise be possible.

While ECC RAM is not always Registered (since you may need the error correction of ECC without the large quantities made possible by Registered memory), almost all Registered memory will be ECC. This is simply due to the fact that systems that use large amounts of memory are almost always going to prioritize stability as well.

ECC Failure Rate Analysis

ECC RAM is theoretically more stable and reliable than standard RAM, but many times theory does not match up with fact. To see if ECC RAM really is more reliable, we looked up our failure rates for ECC and non-ECC RAM over the past 3 years.

One thing to note is that while we have tried many different brands of memory over the years, we have always returned to Kingston due to their consistently lower failure rates - up to 6x better in some cases! Because of this, we decided to include only Kingston desktop/server memory in our failure rate analysis. Including other brands makes ECC RAM look even better, but we feel that comparing within a single brand is a much more realistic comparison.

As the graph above shows, ECC RAM has a much lower failure rate than non-ECC RAM. The ~1% failure rate of the Kingston non-ECC RAM is still very, very good (which is why we primarily use Kingston), but the ECC RAM is even better at an average .24% failure rate.

One thing to notice is that over the past three years, Kingston RAM has become even more reliable over time. This is true for both ECC and non-ECC RAM and is currently at the point where we have not had a single stick of ECC RAM failure this year at all.

While a lower failure rate is certainly great, it is worth a little more investigating to determine what the cause of the failure was. Memory errors or system instability is much worse than a simple no POST failure. A faulty stick of RAM causing the system to not POST is an inconvenience, but is very unlikely to affect the data stored on the system. Memory errors, on the other hand, are much more likely to corrupt data if left unchecked.


The incredible thing about the graphs above is that over the past three years, we have not had a single case of memory errors or system instability caused by ECC RAM. Every single failure was due to either no POST or the system rebooting when we tested the memory for errors. While the rebooting issue is not ideal, the 25% reboot failure actually adds up to only 2 sticks ever with that specific problem, and both were all the way back in 2011.

The failures for non-ECC RAM, on the other hand, are overwhelmingly caused by memory errors. In fact, only 9% of the failures (No post, other/misc, and incorrect size/speed) were the type of failures that would not put your data at risk. The other 91% of failures were the type that you absolutely do not want to see in a server or other system that contains valuable data.

One thing we do want to make clear is that although non-ECC RAM currently has about a 1% failure rate, the testing we perform on all of our systems catches the majority of the issues. In the field, the failure rate for non-ECC Kingston RAM is only about .4%, or roughly one stick for every 250 sticks we sell. So while ECC RAM is certainly important for servers and systems with high-value data, non-ECC RAM is more than stable enough for use in most home or work systems.

Downsides of ECC RAM

ECC is designed to be more stable than traditional RAM, and our failure records show that this is indeed the case. However, there are a few downsides to using ECC RAM. The first, and most obvious, is that not every computer can use ECC memory. Most server and workstation motheboards require ECC RAM, but the majority of desktop systems either won't work at all with ECC RAM or the ECC functionality will be disabled.

Second, due to the additional memory chip and the inherently more complex nature of ECC RAM, it costs more than non-ECC RAM. The amount varies, but you should expect to pay roughly 10-20% more depending on the size of the memory stick. The larger the stick, the higher the price premium.

Finally, ECC RAM is slightly slower than non-ECC RAM. Many memory manufacturers say that ECC RAM will be roughly 2% slower than standard RAM due to the additional time it takes for the system to check for any memory errors. To verify this, we examined multiple benchmarks that we run on each system we produce. By using comparable CPUs (For example: Intel Core i7 4771 3.5GHz Quad Core 8MB versus Intel Xeon E3-1275 V3 3.5GHZ Quad Core 8MB) we found that this 2% estimate to be roughly correct. Our own benchmarks showed a performance hit ranging from .72 to 2.2% which, given normal testing deviations, is right in line with the 2% estimate.

Conclusion

If you have a server or system with high-value data where system stability is of upmost importance, these few drawbacks are very likely not even close to being an issue. The cost of RAM has come down so much recently that even a 20% increase in price only equates to about $10 per stick, which in a server environment is a very worthwhile investment. As for the performance decrease, 2% is such a small amount that it is likely never going to be perceptible outside of performance benchmarks.

At the cost of a little money and performance, ECC RAM is many times more reliable than non-ECC RAM. And when high-value data is involved, that increase in reliability is almost always going to be worth the small monetary and performance costs. In fact, anytime it is possible to do so, we would recommend using ECC RAM.

Tags: ECC, Registered, Memory, RAM
Brad

Are there any desktop class motherboards that support ECC RAM?

Posted on 2013-12-24 19:59:27

On the Intel side, the closest thing would be a more workstation-oriented Xeon motherboard. The Asus P9D WS we use in our Obsidian workstation would be a good example. The more mainstream Core i5 and i7 processors don't support ECC memory, though.

AMD provides support for that type of memory on a much wider range of their processors, though, and so a lot of the corresponding motherboards support it as well.

Posted on 2013-12-24 20:03:19
Ian R

Does the Asus P9D WS support ECC memory? The Asus spec sheet says it doesn't?

Posted on 2014-01-02 03:52:45

Yes, it definitely does! We use it in our Obsidian workstation with ECC. http://www.pugetsystems.com...

Posted on 2014-01-02 03:55:52

From Asus' motherboard specs page for the P9D WS:

"4 x DIMM, Max. 32GB, DDR3 1600/1333 MHz ECC, Non-ECC, Un-buffered Memory " (http://www.asus.com/Motherb...

That is phrased a little oddly, but it means it can take either ECC or non-ECC memory, so long as it isn't buffered / registered.

Posted on 2014-01-02 17:50:29

Crosshair V Formula-Z

Posted on 2015-01-04 04:40:30
agello24

yes.

Posted on 2017-11-20 23:14:52
notmyemail

Thank you for this article. Much appreciated good sirs.

Posted on 2014-09-25 14:24:12
Jouni Järvinen

2% slowness is alot since RAM today hits high numbers of megabytes a second (DDR3 6400MB/s <-> 17066â…”MB/s (17066.666667MB/s) as told by Wikipedia, and probly means per stick instead of the whole system), which means 128MB/s <-> 341.33333334MB/s slowdown (6272MB/s <-> 16725.33333366MB/s) with ECC.

Posted on 2014-11-12 00:56:53
Κωνσταντίνος Κ.

341mb/s for a memory is a joke, you won't even feel it ..on the other hand it might be as low as 0.72% reduction meaning ~123mb/s which is laughable ...but the stability of the system would be many times better. I'd go with ECC if price of the memory isn't an issue and board supports it

Posted on 2017-05-08 17:56:31
mrnuke

I'd like to point out that ECC memory is considered server-grade. They are sold to a market which pays much closer attention to reliability than the consumer market. As a result, ECC RAM is usually subjected to much stricter testing and validation before shipping. This is a big factor in why ECC modules see much lower failure rates.

Noe to addressing the performance drop with ECC. This has more do to with the memory controller. A well designed memory controller should incur no penalty under normal operation.

A little beside the issue, but ECC RAM is usually registered. That would explain the performance drop more than the time it takes the "system to check for any memory errors". To add a twist to this, when using several ranks per channel, registered RAM can actually have an advantage, as it allows the memory controller to issue a 1T command rate, versus the 2T command rate caused by bus loading. An unbuffered dual-rank module has eighteen times the bus loading on the command lines versus a registered DIMM.

Posted on 2014-11-24 08:25:25
keval Patel

hello sir,
i am vfx artist and video editior.
i want to buy workstation but i am confused which one wiill be better.
core i7 4790k or xeon e3
for adobe after effects, premier (4k video editing)
dell or hp??

Posted on 2015-07-13 09:53:20

The Xeon E3 line only goes up to about 3.7GHz, so the i7 4790K (at 4GHz) would be faster. However, for video editing - particularly 4K editing - I would usually advise something even more powerful. Those processors you asked about are both quad-core, but if you move up to the Xeon E5 line then you can get anywhere from 4 to 18 cores... and you can use two CPUs in a pair, for even more performance. Professional video editing workstations usually consist of processors using that sort of technology, though of course that gets more expensive as well.

As for Dell or HP... I'd suggest neither! If you are in a region we serve (the US, Canada, Mexico, etc) I would recommend purchasing one of our Genesis media editing workstations. Or if you are on a budget, and need to stick with just a quad-core processor, check out the Spirit.

Posted on 2015-07-13 17:55:09
Zishy

is the genesis workstation anything other then off the shelf? obviously i would recommend my own brand too but other then a case theres nothing in there you made yourself i asume

Posted on 2015-09-30 18:40:17

The parts we use are all high quality components from well respected brands, and for the most part could be purchased 'off the shelf' as you put it. The value we add isn't in unique components (aside from a few custom acrylic parts we manufacture) but instead falls into three main categories:

1) Our expertise in knowing what specs are best suited to different needs, and helping to guide customers through the various choices to get to the right system for their needs and budget. This also covers our testing and qualification of components before we carry them, to make sure we are willing to put our name and reputation on the line with the products we sell.

2) Professional assembly and testing of the system, making sure that it is well built and stable so that customers can get right to work as soon as they plug the computer in.

3) Lifetime tech support, ensuring that if customers do run into trouble later on they have someone to turn to for help. We don't outsource any of our support, so customers don't have to deal with language barriers or having to go through multiple levels of support techs to get to someone who can actually help them resolve their problem.

Can someone build their own system with the same parts we use? Sure! And many people do. If you have the time and experience to build your own computer it is the lowest-cost option, at least in terms of money alone. But for folks who don't know what they need, or don't have have the time / experience to build it, or who value their time more highly, or who just want to make sure they aren't on their own if a part fails... that is why we are here :)

Posted on 2015-09-30 18:48:10
Zishy

good support can be an important thing to be able to rely on.

Posted on 2016-10-21 09:48:45
Zishy

you should state your budget. i recently bought a HP-Z210 for 199euro that was a barebone and i slapped an E3-1270 in it. it came with 16gb ecc memory and the machine is now running as a server in my home. the same machine can easily be used for video editing and graphics but here you reach a different area. graphics card for your application will be important and the MOST importan part when you do video editing and i guess you also encode and render is to not have harddisks bottleneck you.

in my main desktop machine i use a 6x1tb raid0 just for recording @1440p because i want non compressed raw footage. when i render in vegas i use a different array to write then to read. its the small details that are important.

also you can get older dual socket workstations with 24gb ecc ram and 2x6core 1st generation xeons for dirt cheap nowadays. if its something very specialized you should look into that

Posted on 2015-07-14 12:58:54
Ryan Recio

okay so where would you find a dual socket workstation with 24gb ecc ram and a 2x6core 1st generation xeon ? I'm guessing ebay or something

I was going to buy from dell, but what you say about salvage sounds like a good idea. Btw what do you think of this build ?https://uploads.disquscdn.c...

Posted on 2016-04-15 20:22:29
Zishy

im very sorry i never answered back :) oh you can grab Dell workstations off ebay. the cheapest dual socket workstations with 45nm or 32nm xeons are probably HP Z600, HP Z800 and if you want to be a little more up todate with dual socket 8core sandy bridge-ep you could grab a Z620 or Z820.

the Z800 / Z600 machines are probably the best bang for your buck tough. i think total with my Z800 that i got back into working order was around 750$. I used 2x X5675, 96gb ram. for the rest of the guts i slapped in a few older 500gb disks and raided them for troughput and for OS Disk and recording disk i grabbed 2 samsung 850 evos. all of this is dirt cheap nowadays and you can easily turn these machines into beautiful editing machines.

if you have some older nvidia gfx like a 970 lying around you are golden in terms of cuda possibilities

Posted on 2016-10-21 09:46:48
DomZP

I use simulation software, can you offer any insight into the type of problems that non-ECC RAM failure may lead to. Are we simply talking about software crashing?

In the statistics you have compiled, what is meant by failure rate?

Avoiding workstation processors seems to offer significant cost savings, but this means ECC RAM is not an option.

Posted on 2016-01-18 11:34:44
Jouni Järvinen

Death of the RAM module.

Posted on 2016-01-18 12:33:14

We list the reasons for our recorded failures in the ECC Failure Rate section (https://www.pugetsystems.co..., but most of them are due to either giving memory errors, causing the system to not turn on, or system instability. In a workstation, I would say the biggest risk comes from memory errors and system instability. System instability is pretty straight forward: it simply means that either the software running crashes or the entire system bluescreens. That can be a pain due to lost work, but I would actually consider memory errors to be much more dangerous. What happens there is that the data either gets written wrong to the RAM or is read incorrectly. This can be very significant if you are running calculations and a number suddenly changes. The difference between the number 28 and 60 is only a single binary bit, but can make a calculation give the completely wrong result! Especially for simulations, you don't want that to happen.

As for the cost difference between Core i_ and Xeon CPUs, it depends on what CPU you are looking at. The difference between the Core i3/i5/i7 CPUs and the Xeon E3 is anywhere from the same price to about $50 depending on if you need the Xeon E3 CPU with onboard video or not. For the high end Core i7 and Xeon E5 CPUs, the pricing is also very, very close from the models that are equivalent. The thing with Xeon E5 is that you get a much wider range of options (more and less core counts, higher and lower frequency, etc.). Workstation boards and ECC RAM iteself is also a bit more expensive, but I don't think you should end up with more than about a $150-200 price difference between a standard system and a workstation with ECC memory (at least when the two systems are equivalent)

Posted on 2016-01-18 17:53:52
DomZP

Thanks for the explanation about failures. i wasn't sure what the actual impact would be for some of the failure modes.

The commentary on costs is also very useful. My experience had been that the price gap was higher, but I had been looking at the E5-2667, when the E5-1680 would have been more appropriate, in comparison with the i7-5960.

Posted on 2016-01-19 09:14:32

The equivalent to the i7-5960X is the Xeon E5-1660 V3 which according to Intel should be about $80 more expensive. The E5-1680 V3 and E5-2667 V3 don't really have a Core i7 equivalent, however, and both are a bit odd so you can't really compare pricing. The E5-1680 V3 is the absolutely top of the line single CPU Xeon processor right now and given how tight we have found supply is, I believe it is actually difficult for Intel to manufacture. So to compensate they have the price set pretty high.

For the E5-2667 V3, one thing to be aware of is that the E5-2___ processors are actually designed to be used in dual CPU setups. They work great in a single CPU motherboard (we do it all the time), but they have additional technology built into them that allows them to work in conjunction with a second CPU. This is mostly through the addition of a second QPI lane, but it really raises the price. The E5-2667 V3 should be right in between the Xeon E5-1660 V3 and Xeon E5-1680 V3 in terms of performance, but even with the price premium on the E5-1680 V3 the E5-2667 V3 is around $300-$900 more expensive. In addition, the dual CPU Xeons are the only one where you can get more than eight cores currently, so as you increase the core count above eight, the pricing pretty quickly gets kind of crazy.

Posted on 2016-01-19 18:04:35
goblin072 .

Some WS motherboards support 4 types of ram. I have read ECC performance hit is less than 1 percent in games. But that was non buffered ECC.

It would be interesting to see Benchmarks GAMES and Non Games

64 Gigs of non ECC

64 Gigs of unbuffered ECC

64 Gigs of Buffered ECC

64 Gigs of LRDIM ECC

Which would you want in you workstation? I am talking about performance of both games and non game applications. Is unbuffered ECC going to be the fastest or is buffered ECC?

Posted on 2016-02-16 15:33:09

We actually tested that, with the previous generation of memory (DDR3) and without including LRDIMMs. I would expect the same basic results would hold true for DDR4 as well, though:

https://www.pugetsystems.co...

Posted on 2016-02-16 20:02:22
goblin072 .

Nice job!! I think you are the only place on the web that took the time to test this. I don't think including a gaming benchmark was a bad thing. Lets face, most computer users play games and probable would be curious how much they are loosing if they used registered vs non buffered ecc. Next you will need to include that LRDIM ECC. Thanks for the nice testing.

Posted on 2016-02-17 01:07:48
Assin Ontivi

Note that ECC ram must be paired with a compatible CPU in addition to other compatible hardware. In the case of Intel CPUs, only the Xeon chips appear to support ECC RAM.

Querying your Windows system for ECC:

From command prompt: wmic memphysical get memoryerrorcorrection

Here are the return codes:

0 (0x0) Reserved

1 (0x1) Other

2 (0x2) Unknown

3 (0x3) None

4 (0x4) Parity

5 (0x5) Single-bit ECC

6 (0x6) Multi-bit ECC

7 (0x7) CRC

Posted on 2016-04-05 17:35:27
funklord

A 2% performance hit is nothing compared to the severe inconvenience of memory corruption.
I'd choose ECC for every machine including phones and tablets even if it meant a 50% slowdown.

Posted on 2016-05-03 13:15:52
Siegfried

Are you sure that your statistics are in percent?
if you write "is only about .4%, or roughly one stick for every 250 sticks" that means that it is permille (based on 1000) not percent.?

Posted on 2016-07-13 08:02:58

1% = 1 out of 100
0.4% = 0.4 out of 100, or 4 out of 1000
4 : 1000 = 1 : 250

Posted on 2016-07-13 15:28:09
MODISAOTSILE SETSHOGOE

Morning Mr George I'm trying to get myself a nice workstation that can do simple video editing and rendering and so far my brother brought me 2x ECC 16gb ram and i wanna know which motherboard and CPU i must buy as i'm not big on this machines but sucker for performance and time and difinetly no errors as they cost lots of time and money

Posted on 2018-03-21 07:11:35

More information would be required in order to answer your question. What generation of memory is that? DDR3, DDR4? And is it plain ECC or Registered ECC? Those things will impact what CPUs might be compatible.

Posted on 2018-03-21 16:19:57
MODISAOTSILE SETSHOGOE

Ooh sorry about not giving you more information. I've got DDR4 ECC Lenovo SK hynix Ram which I've put on the standard 1151 DDR 4 motherboard and its not working and I wanna know which boards and processors you can recommend for me that will be good for basic video editing and playing. Thanx for your response it means a lot to me thnx once again

Posted on 2018-03-21 17:07:56

It looks like there are both normal ECC and Registered ECC (RDIMM) modules of that type and manufacturer, so more specifics will still be needed. Honestly, though, I have a hard time recommending buying a new CPU and motherboard just to match some RAM. You'd probably be better off selling the RAM and then buying the type that matches your existing system.

Posted on 2018-03-21 17:15:34
MODISAOTSILE SETSHOGOE

Okay thanx I think maybe I should do that and rebuild new system from scratch to suit my needs and any recommendations as what I should buy that's currently on The market that won't give me headaches in a long run?

Posted on 2018-03-21 17:24:09

That sounds like a good plan :)

As for advice on what sort of hardware / specs to get, take a look at our Solutions / Recommended Systems section:

https://www.pugetsystems.co...

Even if you build a new system, rather than buying one from us (or another system builder), the information on those pages about how different applications perform should be very helpful.

Posted on 2018-03-21 20:57:03
Johnny test592

https://uploads.disquscdn.c... is this ecc or non ecc

Posted on 2017-05-18 02:37:54
Jouni Järvinen

That tiny chip in the middle could be the corrector, but I doubt it. What's the other side like ?

Posted on 2017-05-18 11:36:46
Johnny test592

i just does not have the small chip

Posted on 2017-05-18 19:26:22

That is a non-ECC stick of RAM. If it was ECC you would have 9 of the square memory chips, but this stick only has 8. The small chip in the middle is probably a SPD chip https://en.wikipedia.org/wi...

Posted on 2017-05-18 19:34:37
Johnny test592

ok thx

Posted on 2017-05-18 19:58:04
Epumbi Escobaric

That might be an ECC if it is for the server edition, i saw a similar with such architecture and was ECC look out here.. https://www.serversupply.co...

Posted on 2017-11-15 06:11:41

It also stops Rowhammer.

Posted on 2018-03-26 19:28:39
Naum Rusomarov

Great article!

In a workstation, general system instability can be pretty devastating. If you have 20 nodes and one of them randomly reboots or shuts down you can remove it and deal with it later because you have 19 nodes left. If your workstation randomly crashes then that's a problem that you have to deal with right there. And diagnosing why your system behaves weirdly can be a pretty daunting experience even for those who make money out of it. So I'm not sure non-ECC RAM is worth it for workstations unless you've got some specific requirements for much faster memory.

Posted on 2018-08-04 14:53:42