[SOLVED] What's the difference between DIMM, UDIMM, SO-DIMM?

[PrimalSins]

I'm planning on getting more ram for my pc, as I only have a single 8gb stick. I know that my current ram is DDR4 so I was obviously looking for the same type of ram, another 8gb, but I saw that it's also "DIMM" and i was looking around and found that there's not a lot of 8gb single stick ram for DIMM being sold. Is there a difference in if I use DIMM, UDIMM or SO-DIMM?

My PC is a prebuilt that I bought a few years ago when I didn't know better, it only has 2 ram slots and is currently using one of them for an 8gb stick.

 

[RealBeast]

UDIMM is a DIMM that is not registered (buffered), typical consumer computer memory.
SO-DIMM is a different pin layout for laptops usually.

edit: note that memory is sold to work as a set, even another of the same may not work -- although it usually does. Mixing speeds or timings will make success much less likely.

 

[USAFRet]

What is the actually difference between UDIMM and DIMM?

I've been searching for this answer for awhile now, and have yet to get a clear/concise answer. Between these forums and other tech forums, I've found conflicting answers. Some say there is no difference, while others say there is. One particular answer in these forums, state UDIMM is for...

forums.tomshardware.com

Also, adding a single 8GB to the current one may not work.
RAM is only guaranteed to work in the set that are sold. Adding another may work, it may fail.

 

[PrimalSins]

What is the actually difference between UDIMM and DIMM?

I've been searching for this answer for awhile now, and have yet to get a clear/concise answer. Between these forums and other tech forums, I've found conflicting answers. Some say there is no difference, while others say there is. One particular answer in these forums, state UDIMM is for...

forums.tomshardware.com

Also, adding a single 8GB to the current one may not work.
RAM is only guaranteed to work in the set that are sold. Adding another may work, it may fail.

So then it's smarter to just buy 16gb in a set of two 8gb sticks and replace the old 8gb stick? But then does it matter if I get a UDIMM or DIMM or whatever?

 

[USAFRet]

So then it's smarter to just buy 16gb in a set of two 8gb sticks and replace the old 8gb stick? But then does it matter if I get a UDIMM or DIMM or whatever?

Precisely!

 

[PrimalSins]

Precisely!

There's so many different types of DIMM's though, like UDIMM and RDIMM and SO-DIMM, I don't know which one's better though. I found some info about the different ones being for different things like server hosting and stuff, but I'm just generally confused on which to look for.

 

[SamirD]

There's so many different types of DIMM's though, like UDIMM and RDIMM and SO-DIMM, I don't know which one's better though. I found some info about the different ones being for different things like server hosting and stuff, but I'm just generally confused on which to look for.

You have a consumer system so you're technically using udimms (unbuffered dual inline memory module). These come in ecc and non-ecc variants. They also come in ecc buffered aka ecc registered modules (RDIMMs)--these are typically only for servers and workstations.

SODIMMs are for laptops because they are physically smaller (unbuffered dual small outline inline memory module). These are typically all non-ecc.