Question What do "Non-ECC" and "Unbuffered" mean?

[Manuel Jordan]

Hello Friends

at A-Tech 4GB DDR2 800MHz SODIMM PC2-6400 1.8V CL6 200-Pin Non-ECC Unbuffered Laptop RAM Memory Upgrade Module

It has the "Non-ECC" and "unbuffered" terms.
what do mean each one?
Of course it about RAM Technology.

If the "unbuffered" term exists, I am assuming "buffered" exists too ... what is better and why? Same question about "Non-ECC" and "ECC"

Thanks in advance.

 

[Eximo]

Error Checking and Correcting. Instead of 8 memory chips there are usually 9, and any flipped bits get detected and repaired before the data is used. Buffered memory is a way to increase memory capacity with less strain on the memory controller, effectively.

Typically three types of system memory you can potentially use:

The most common, and all that most consumer products support, is unbuffered and non-ECC. The memory data is reset every clock cycle, and if it is wrong, can cause a system crash.
Buffered memory essentially takes some stress off the memory controller and allows more memory sticks to used. Not that common, but some AMD desktop boards do support it.
Server and high end workstation memory is almost always ECC and buffered and allows for large memory sets that aren't likely to cause a crash. Wherever processing is tied to money making, you will find it.

The downsides to ECC is higher latency and lower maximum speeds. The upside is that you can have a lot more of it, which is where you get your quad and six channel memory setups with 1TB+ of memory.

DDR5 unbuffered non-ECC actually does have a type of error correction built in. Basically a mid-way point between ECC and non-ECC memory. This is necessary because of the very high speeds DDR5 can achieve, which can lead to errors.

 

[Manuel Jordan]

Thank you ...

Being curious, for example see the following link

Kingston Technology KVR16LS11/8 8GB 1600MHz DDR3L (PC3-12800) 1.35V Non-ECC CL11 SODIMM Intel Laptop Memory

It is Non-ECC too ... but how to know if is unbuffered or not?

Again versus

A-Tech 4GB DDR2 800MHz SODIMM PC2-6400 1.8V CL6 200-Pin Non-ECC Unbuffered Laptop RAM Memory Upgrade Module

About the former (Kingston): I have that memory as pair in a Toshiba (2 x 8GB) and so far goes well everything.

 

[Eximo]

Amazon listings aren't definitive, every seller can write down what they want.

Newegg tends to have the proper fields populated, for the most part.

https://www.newegg.com/kingston-8gb-204-pin-ddr3-so-dimm/p/N82E16820239697

Kingston doesn't actually say in their details document, which is sad. But Kingston is a fairly common consumer and enterprise memory maker. They likely put the distinction on their ECC memory and assume that people buying Kingston consumer memory don't really need to know.

But regardless, your typical consumer memory is non-ECC, unbuffered.


Oddly the very rare unbuffered ECC memory will work in non-ECC platforms. But buffered memory only works in motherboards that specifically support it.

 

[Manuel Jordan]

Thanks again for the reply

Should I assume that for laptops as HP and Toshiba and perhaps MacBook Pro use "non-ECC, and unbuffered"?

 

[Eximo]

Thanks again for the reply

Should I assume that for laptops as HP and Toshiba and perhaps MacBook Pro use "non-ECC, and unbuffered"?

Unless otherwise specified, yes.

Not sure how far back you have to go for a MacBook to not have soldered memory though.

 

[Manuel Jordan]

Thanks for the reply

For a Toshiba Satellite L845-SP4146KL was installed Kingston Technology KVR16LS11/8 8GB 1600MHz DDR3L (PC3-12800) 1.35V Non-ECC CL11 SODIMM Intel Laptop Memory (observe the Non-ECC term) and for an Apple MacBook Pro "Core i7" 2.9 13" Mid-2012 Specs theoretically the mentioned RAM is compatible too.

Now for an Apple MacBook Pro "Core i5" 2.3 13" Early 2011 Specs, according with the seller the same mentioned RAM is compatible too, even when this MacBook Pro asks for a minor frequency 1333 vs (1600)

Therefore, because the other ram A-Tech 4GB DDR2 800MHz SODIMM PC2-6400 1.8V CL6 200-Pin Non-ECC Unbuffered Laptop RAM Memory Upgrade Module has the "Non-ECC Unbuffered" term, it rose this doubt