Add memory to existing 16GB setup with 2x4 and 1x8 GB

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boland

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#273394 20-Aug-2020 09:28

Got a desktop PC, and I'm running low on memory while developing code. It has 2 sticks of 4GB and 1 of 8GB currently installed. I was planning to add 16GB memory, and I know the best setup is to have similar sized memory modules, but that means it becomes a bit more expensive than my budget :)

My PC is currently fast enough for what I'm doing with it, just wondering what the benefit is of replacing it with 2x16GB vs just adding 1x16GB?

Dynamic

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#2544951 20-Aug-2020 09:58

My Googling in the past suggests matching pairs etc of memory to get dual-channel mode is negligible real-world performance gain unless you are doing some serious number-crunching. I wouldn't bother about it.

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Andib

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#2545058 20-Aug-2020 11:13

Unless you have a really picky motherboard you will be fine having un matched memory. You lose Dual channel support, but you never had that anyway running only 3 DIMMs anyway and unless you're gaming I doubt you'd really notice the difference.
Depending on what generation CPU & chipset you have you may only be able to have a maximum of 32GB so buying 2x16GB DIMMs is probably a waste.

I'd still recommend sticking the 2x4GB DIMMs into the same channel so these run in dual channel mode.

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boland

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#2545067 20-Aug-2020 11:27

Thanks! It's a ~1 year old set up, and I'm not gaming. Will make sure the 2x4GB DIMM are in the same channel.

And thanks for confirming that I wouldn't notice the difference.

PabloD

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#2545071 20-Aug-2020 11:31

Negligible performance differences aside, you can still has dual-channel if you whack another 8gb stick in there. That's 12GB per channel if you configure it right (a 4gb and a 8gb in each channel, your motherboard will have the slots labelled with what channel they are).

If they are mismatching sticks then it can be a little plug'n'pray that they're compatible in this configuration, but 90% of the time it's fine.

edit: that's assuming 24GB is enough for you

PabloD

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#2545075 20-Aug-2020 11:34

I'd still recommend sticking the 2x4GB DIMMs into the same channel so these run in dual channel mode.

They need to be in different channels to run in dual channel.

Dynamic

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#2545076 20-Aug-2020 11:36

PabloD: If they are mismatching sticks then it can be a little plug'n'pray that they're compatible in this configuration, but 90% of the time it's fine.

We *never* have trouble, but this is likely because we buy Kingston system-specific third party memory. https://www.kingston.com/en/configurator

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PabloD

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#2545081 20-Aug-2020 11:45

Dynamic:

PabloD: If they are mismatching sticks then it can be a little plug'n'pray that they're compatible in this configuration, but 90% of the time it's fine.

We *never* have trouble, but this is likely because we buy Kingston system-specific third party memory. https://www.kingston.com/en/configurator

Holy carp it even has links to local NZ stores :s well i never

Dynamic

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#2545089 20-Aug-2020 12:07

That memory search is a fantastic tool. Very rarely have I not been able to find something I'm looking for.

Synnex and Ingram are wholesalers only, so as a consumer (?) you won't be able to buy direct from them. There are hundreds of part numbers which can't all be kept in stock in NZ, so anticipate a 2 week lead time. In normal times, Synnex told me they order from Kingston on a weekly basis and receive the order exactly a week later, dispatching to us the next day.

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SpartanVXL

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#2545279 20-Aug-2020 14:36

It really depends on what you’re doing. In most cases dual-channel or single-channel won’t have too much impact. If you’re relying on bandwidth then you’ll be wanting to use dual-channel (double data rate DDR, it’s in the name) as without you’re running at half the transfer rate you could be.

For example if you’re running a Ryzen system, the infinity fabric interconnect benefits from having faster ram if you’re doing any high cpu workloads.

At the end if the day though, if you just need more physical memory then you can configure them anyhow you like