Guys can you please explain how does this dual channel/quad channel thing work and what are the actual performance benefits of one versus the other? I have a couple questions:
If my CPU supports dual channel does it matter if I run 1 x 16 GB ram, 2 x 8 GB ram or 4 x 4 GB ram?
Does dual channel only work if you have only 2 ram modules? Does it turn off if you have 4 ram modules? Or does it only work for two of the ram modules and not for the other two?
What kind of workload benefits from dual channel and quad channel the most?
Is dual channel / quad channel relevant for compiling code?
Is dual channel / quad channel relevant for gaming?
In general is there any rule of thumb that it’s better to have as few ram modules as possible e.g. 2 x 32 gb is better than 8 x 8 gb?
In most cases, you want an EVEN number of ram modules for dual channel systems, 1 no good, 2 good, 4 good
See #1
All workloads benefit from faster memory, but usually the more threads you run at once, the more ram is getting hammered for information.
4, 5. See #3
If you overclock your ram, or want higher clock speeds in general, the fewer modules the better BUT also the fewer the bytes the better. Easier to overclock 8gb than 64gb, and 256gb, forget about it.
You mention 32GB modules, those are very new so don’t assume they’ll just work in whatever motherboard. Good idea to check the website for your motherboard and see if they support those monster modules.
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More bandwidth. So the clock speed is still 2666, or 3200 or whatever, but with dual or quad channel, you have more lanes on the highway. So that lets the CPU and IO cards exchange more data with RAM per clock.
more channels basically means cpu has more direct/short paths to memory addresses at any given time. so dual/quad channel motherboards will be faster in operation than their opposites.
For optimal performance you want to have at least the number of channels in DIMMS. In most cases the jump from single to dual (which is max on the mainstream platforms) is something I would always recommend. On the higher end systems going from dual to quad channel can still be beneficial but in a lot of cases it isn’t a game changer.
There have been triple channel configurations in the past and there are also hex and octo channel systems btw.
Highly depends on the said workload you trow at it.
But in general, if your particular platform supports dual channel.
Then i would always recommend to use at least 2 memory modules boaght as a kit.
Running dual channel basically means that you get more bandwith available vs only running 1 module single channel.
Platforms with dual channel support like AMD AM4, or Intel Z390 for example,
the cpu has two memory channels.
The two memory channels support each up to two modules per channel.
So nomatter if you install two or four memory modules,
it still will be dual channel.
Quad channel platforms like Intel HEDT X299 or AMD Threadripper platforms,
the cpu has four memory channels,
which then can support two memory modules per channel so 8 in total.
But again no matter if you populate all 8 slots or just 4,
it still will be quad channel when appopriate slots are populated.
Also like @noenken above also said its recommended,
to buy at least the amount of dimms that your particular platform supports in channels.
Quad channel workloads are typically benefitical,
in situations that you do load allot of work in memory.
So like large databases or spreadsheets that sorta things.
yes.
Dual channel YES (depends on the game).
Quad channel NO not really.
Depends on the platform and workloads again.
But a general rule of thumb, the more memory slots you populate,
the lower the potential achievable memory overclock speed likely will be.
And with “likely will be” i mean that there are also other variables that come into play with this rule.
But i don’t really want to get too deeply into this.
Because there are many variables that come into play here.
And that will result in a pretty complex story.
Yes, dual (or quad, of hex, etc.) channel makes RAM throughput faster, however modern CPUs have pretty big caches, so it mostly doesn’t matter except when it does ( ) - e.g., you’re running an application that needs fast access to a LOT of data. Possibly games, too.
If your workload fits in CPU cache there will be essentially no difference.
If it does NOT fit in CPU cache, the difference can be huge.
All other things being equal, if you can - run multiple channels if you can. e.g., instead of buying 1x 16 GB stick, buy 2x8 instead, and you’ll get a performance boost under streaming media/other streaming (or other high memory bandwidth) applications.
If you have 4 slots, you will generally have 2 slots per channel. So even with 2 sticks, you want to make sure both sticks are in different channels (consult your motherboard manual, it will indicate which ones to use).
If you have 4 sticks you will still have dual channel, but twice as much capacity. Unless of course you have a quad channel capable motherboard (normally 8 slots) - in which case you will want to make sure the sticks are again all in different channel’s slots.
) - e.g., you’re running an application that needs fast access to a LOT of data. Possibly games, too.