Unbuffered non-ECC DDR4 vs DDR5 for data integrity and reliability

[Wolverine2349]

Yes I know full ECC is recommended and preferred, but if you only had the choice of JEDEC spec RAM without ECC, which is more reliable DDR4 or DDR5?

I have heard even consumer level DDR5 has some ECC built into the chips itself but only at the RAM level where as DDR4 does not. Does that offer any better protection than non ECC DDR4, but not as good of course as full on ECC DDR4 or full on ECC DDR5?

Or does it make 0 difference?

How about other ways of reliability like the RAM sticks themselves and IMC and such for consumer grade non ECC DR4 vs DDR5?

 

[Arwen]

I take that built in ECC to DDR5 as allowing manufacturers to sell chips with defects that are automatically corrected. Only if their are too many defects, does the chip fail and be thrown away. (Or sold for smaller size, slower speed or ???)

DDR4 has to have perfect cells to pass any reasonable memory test. Those tests are;

1. At the chip factory
2. After chip is installed on memory module boards
3. After the consumer gets it, then runs memtest

One advantage of DDR5 is that it appears to have 2 x 32 bit data buses. This would allow dual access to a single DDR5 DIMM module.

 

[Wolverine2349]

I take that built in ECC to DDR5 as allowing manufacturers to sell chips with defects that are automatically corrected. Only if their are too many defects, does the chip fail and be thrown away. (Or sold for smaller size, slower speed or ???)

DDR4 has to have perfect cells to pass any reasonable memory test. Those tests are;

1. At the chip factory
2. After chip is installed on memory module boards
3. After the consumer gets it, then runs memtest

One advantage of DDR5 is that it appears to have 2 x 32 bit data buses. This would allow dual access to a single DDR5 DIMM module.

The last thing you said about 2 X 32 bit data buses that would allow dual access to a single DDR5 DIMM module, is that a reliability/stability/error correcting advantage or performance advantage or both?

 

[HoneyBadger]

Performance advantage - each DDR5 DIMM behaves like a "dual channel" configuration.

Purely from a "personal computer" standpoint, and speaking from my own experience, I would say that the much higher clock speeds of DDR5 do mean that it is running closer to the "bleeding edge" of stability - anyone who's experienced long DDR5 training times on initial boot of a highly-tweaked system with tight timings would likely concur with that.

To summarize the ZFS/ECC thing, Matthew Ahrens probably said it best:

There's nothing special about ZFS that requires/encourages the use of ECC RAM more so than any other filesystem. If you use UFS, EXT, NTFS, btrfs, etc without ECC RAM, you are just as much at risk as if you used ZFS without ECC RAM ... I would simply say: if you love your data, use ECC RAM. Additionally, use a filesystem that checksums your data, such as ZFS.

 

[Wolverine2349]

Performance advantage - each DDR5 DIMM behaves like a "dual channel" configuration.

Purely from a "personal computer" standpoint, and speaking from my own experience, I would say that the much higher clock speeds of DDR5 do mean that it is running closer to the "bleeding edge" of stability - anyone who's experienced long DDR5 training times on initial boot of a highly-tweaked system with tight timings would likely concur with that.

To summarize the ZFS/ECC thing, Matthew Ahrens probably said it best:

Is that true even for JDEC spec DDR5 in Gear 2 despite its much loser latency timings?

 

[HoneyBadger]

Put it this way - I've never had to wait several minutes staring at a black screen after assembling a DDR3/4 system. This seems to be something new to DDR5, even at "stock" DDR5-4800 speeds.

 

[rvassar]

Put it this way - I've never had to wait several minutes staring at a black screen after assembling a DDR3/4 system. This seems to be something new to DDR5, even at "stock" DDR5-4800 speeds.

DDR4 can still have excessive training time. Some of the 1Tb+ servers can take 5 minutes or more to train all the DIMMs. It's just that most of those servers have the courtesy of throwing a splash page up with a progress bar that says "Configuring Memory" or some such...

 

[asap2go]

Performance advantage - each DDR5 DIMM behaves like a "dual channel" configuration.

Purely from a "personal computer" standpoint, and speaking from my own experience, I would say that the much higher clock speeds of DDR5 do mean that it is running closer to the "bleeding edge" of stability - anyone who's experienced long DDR5 training times on initial boot of a highly-tweaked system with tight timings would likely concur with that.

To summarize the ZFS/ECC thing, Matthew Ahrens probably said it best:

If someone is interested in the reasons for the necessity of RAM training:
Basically its measuring and adjusting for the delay times for adressing individual adresses/chips.
The higher the frequency and the more memory chips in a DIMM the more training is necessary.
That does not mean DDR5 is any less stable than DDR4. But the performance improvement isn't free.

Better explanation:

https://www.allaboutcircuits.com/news/boosing-memory-performance-age-ddr5-introduction-ddr-training-modes/

 

[Wolverine2349]

Thanks for all the replies.

After all I am going to go with non-ECC Unbuffered DDR4 with a Coffee Lake Core i5-9600K.

There was 1 mini ITX board I could find with 6 SATA ports and it was an ARock H370M-ITX. Its on the way scheduled to be delivered next week and there was one left on some Amazon Seller and nothing else except overpriced ebay sellers form China which would have taken weeks

There also was a Gigabyte H270 mini ITX board, but was limited to only 6th and 7th Gen Intel.

The H370M was a bit overpriced at $199, but hey it was not bad and all there was that met needs so I got it. Now if it was much more than maybe I would not of.

There were no AM4 mini ITX boards nor any Intel 10th Gen or newer on consumer side.

There were 0 AM5 boards and in fact only 1 AM5 mini ITX board with even 4 SATA ports.
No Intel 12th and 13th Gen had more than 4 SATA ports though almost all had 4 unlike Ryzen 7000.

I also did not want to absorb the cost and hassles of server grade hardware and to get more than 4 SATA ports and SAS adapters and such and the hassles they may bring after further thinking.

Though I am getting 32GB DDR4 2666 RAM that is JEDEC SPEC so no XMP and thus no overclocking which should be even more reliable though not as good as ECC. And it matches the 2666 RAM support speed of Intel Coffee Lake i5 and i7 series per Intel website rather than unsupported but used everywhere XMP (which is really overclocking without them telling you for DITY builds) RAM.

Though this is all for personal home data not mission critical though its important to me, but not really important enough to go ECC just as I do not go ECC on gaming rig and other browsing laptop.

So I struck a compromise no ECC, but making sure to go JDEC specs as well which not as good as ECC, but better than just XMPing RAM as far as reliability.