can you use just one dimm

[raknarius]

building a friends pc on a super tight budget, its on a mini itx system with just two slots, can he use just one 8gb dim now and add one later, will it perform badely till theres a second dim?

 

[shortstuff_mt]

You can use a single stick of RAM. Obviously the RAM won't run in dual-channel mode, but the performance difference won't really be noticeable. If he wants to add RAM later then he should make sure to get the exact same model if possible to avoid compatibility issues.

 

[EonW]

It will work okay with only one dimm, just not quite as well as it would under dual channel with two, but not badly as you fear. If you are going budget and not using it for intensive apps, 4GB may be enough until you can get another (matching) stick.

 

[2x4b]

Yes, you can.
Make sure you read the motherboard's manual, it will indicate what slot to put it in, and what memory makes and models are compatible, and thus guaranteed to to work (QVL) in the board. It will also tell you what you need to know about purchasing another module in the future that is compatible with the one you are buying now.