XPS 8960, 16GB memory upgrade?

"From a CPU performance standpoint, is it better to have two 16gb memory sticks or one 32gb stick??"

Two DIMMs will take advantage of dual channel technology, so 2 x 16GB will be faster than 1 x 32GB ... in theory. In real life, unless you have a particularly demanding use case, I doubt you'll notice the difference.

I replaced the single 8GB DIMM that shipped with my computer with 2 x 16GB DIMMs from Crucial. It's one of the easiest (and least expensive) upgrades you can do.

"I assume that if I get a second stick, it should have the same latency value as the existing stick."

If you get the same OEM 16GB memory stick, yes. Dell cannot speak to 3rd party retail memory.

* Go back to the top of this XPS Desktops board
* Open, "FAQ XPS Desktops"
* Open, "FAQ XPS 8960"

"I assume that if I get a second stick, it should have the same latency value as the existing stick."

Don't assume. Get an exact match by using the memory selector on the seller's website, e.g., Upgrades.

It is wise to get a matched kit of RAM. A second stick of a different brand may have same latency values or may have the same specs but it is not the same. It will confuse the  memory controller on the CPU. DDR5 RAM modules are designed to run as a matched pair. I am using Crucial RAM presently in one of my PCs and it performs well. Plug & play so to speak.

Hope this helps.

@MastiffX​ Doing this does not always guarantee it will work. Some time ago, I contacted Crucial and got a memstick that their compatability webpage stated it would work.  It didn't.  Talked to Crucial and they said they do not guarantee compatibility.  Pay your money, take a chance

@MastiffX​ One reason for the DDR5 memory architecture is to somewhat relieve the memory bottleneck on a single channel RAM (e.g. DDR4) when trying to serve multiple cores.  The conventional guideline of replacing memory in pairs is based on the fact that the  memory architecture of the time was single channel.  
I am assuming that adding a second memory module would expand the existing channels and not add channels. Guess I have to spend some time with the schematics of DDR5 and see how they work.

You are correct "Pay your money, take a chance". Crucial, if their product is not compatible, does accept returns with subsequent refunds. With pre-built PCs, there is always a possibility of a compatibility issue using non-OEM components. One can always purchase a single matching Dell RAM module. More expensive but guaranteed to work, with a warranty too.