Mixing RAM Sizes

[aandril]

I've been told years ago that mixing RAM is bad, even if it's different sizes.

 

But just recently the idea came up and I searched Google and a result had said that mixing sizes is fine, but not to mix DDR types, Such as a DDR3 with a DDR4.

It also says mixing RAM speeds are a different story.

 

My question, so what's the confirmed answer, is it okay to mix sizes so long as the type and speeds are the same?

[porina]

Mixing speeds are fine (although you end up at the lowest of the modules)

Mixing sizes are fine, although you may end up losing multi-channel performance.

Mixing DDR3 with DDR4 is impossible as far as I'm aware, at least I'm not aware of any mobo that will take both. Skylake did support both, but I think mobo manufacturers put one or the other type on.

[aandril]

3 minutes ago, Sierra Fox said:

It's only bad if you're attempting to run dual channel. Otherwise it does not matter

Is running dual channel automatic or can I choose not to have it? 

 

I've never really looked into dual channel, but apparently it's only available on certain motherboards?

[Crunchy Dragon]

-Moved to CPUs, Motherboards, and Memory-

[Sakkura]

3 minutes ago, aandril said:

Is running dual channel automatic or can I choose not to have it? 

 

I've never really looked into dual channel, but apparently it's only available on certain motherboards?

Dual channel is available on just about anything today. Some boards also allow triple or quad channel memory.

 

Dual channel is automatic with simple setups, like 2 identical sticks. Once you start mixing memory, especially with different capacities per stick or an odd number of sticks, it can get complicated.

[aandril]

1 minute ago, Sakkura said:

Dual channel is available on just about anything today. Some boards also allow triple or quad channel memory.

 

Dual channel is automatic with simple setups, like 2 identical sticks. Once you start mixing memory, especially with different capacities per stick or an odd number of sticks, it can get complicated.

I'm confused. Sierra Fox said it's fine to mix as long you're not running duel channel, and you're saying dual channel is automatic and mixing gets complicated.

 

Two different answers.

[aandril]

Can I mix DRAM and DIMM?

[Sakkura]

34 minutes ago, aandril said:

I'm confused. Sierra Fox said it's fine to mix as long you're not running duel channel, and you're saying dual channel is automatic and mixing gets complicated.

 

Two different answers.

Getting the system to run should be pretty simple. Whether it will be in dual channel mode is more complicated. It might end up in single channel mode, or in flex mode where part of the memory is in dual channel and part is in single channel.

21 minutes ago, aandril said:

Can I mix DRAM and DIMM?

DRAM is a generic name for all kinds of dynamic RAM chips. They're used in lots of different things, including DIMMs. For a desktop system, only DIMMs will work.