What is dual channel, quad channel etc

[JoshCanHearYou]

Me and my friend are having a fight over what dual channel and quad channel memory exactly means. He says that 1 kit of two sticks of ram is single channel (which it clearly isnt) and 2 kits of 2 sticks is dual channel. 

Can you please clarify the meaning so i can prove him wrong.

Thanks!

[DarkSmith2]

Quote

Dual-channel architecture requires a dual-channel-capable motherboard and two or more DDR, DDR2, DDR3, or DDR4 memory modules.

https://en.wikipedia.org/wiki/Multi-channel_memory_architecture

[JoshCanHearYou]

This kid thinks a ryzen 5 1500x would bottleneck a gtx 1050

[Windows7ge]

Even if this is all fake I'll entertain it since I'm bored.

 

When a package of RAM says Dual channel it's literally just because theirs two sticks in the package and because their certified to work with on another. If the motherboard says it supports quad channel you can use two dual channel kits it's just that there's a very narrow chance it won't work. Once together and booted it is a quad channel configuration.

[LienusLateTips]

3 minutes ago, Windows7ge said:

Even if this is all fake I'll entertain it since I'm bored.

 

When a package of RAM says Dual channel it's literally just because theirs two sticks in the package and because their certified to work with on another. If the motherboard says it supports quad channel you can use two dual channel kits it's just that there's a very narrow chance it won't work. Once together and booted it is a quad channel configuration.

Or if you use two single sticks in different kits together, that'll likely be dual channel.

[Windows7ge]

1 minute ago, JDE said:

Or if you use two single sticks in different kits together, that'll likely be dual channel.

Or if you buy two 4 stick kits and somehow you have a motherboard that supports Octa-channel the "channel" of which it is is really just a matter of how many stick you have. Don't quote me on it but I think theirs some motherboards that support tri-channel. Pretty sure penta and hepta channel don't exist. mono-channel does.

[LienusLateTips]

1 minute ago, Windows7ge said:

Or if you buy two 4 stick kits and somehow you have a motherboard that supports Octa-channel the "channel" of which it is is really just a matter of how many stick you have. Don't quote me on it but I think theirs some motherboards that support tri-channel. Pretty sure penta and hepta channel don't exist. mono-channel does.

All X58 I believe are tri channel

[Windows7ge]

1 minute ago, JDE said:

All X58 I believe are tri channel

I do believe it was a feature on some older motherboards. I'm not quite sure if there's any remotely modern boards that support it. Realistically it wouldn't be worth it to develop it with today's systems. If you need more memory bandwidth than dual then quad has you seriously covered. That or if you're seriously just that big of a memory hog and you maxed out your quad memory slot motherboard.

[Mira Yurizaki]

40 minutes ago, JoshCanHearYou said:

Me and my friend are having a fight over what dual channel and quad channel memory exactly means. He says that 1 kit of two sticks of ram is single channel (which it clearly isnt) and 2 kits of 2 sticks is dual channel. 

Can you please clarify the meaning so i can prove him wrong.

Thanks!

Multi-channel memory means the system can combine the data channels used in RAM to effectively increase the amount of data that can be transferred at once between the CPU and RAM. This is a motherboard + CPU feature. The number of RAM modules that you buy in a kit is not indicative of anything. You can buy single sticks from the same lot and put them in a multi-channel system. It's just that buying, for example, two sticks from a dual-channel memory kit is a factory guarantee that it'll at least work in a dual-channel system. I've heard that motherboards can be finnicky about not allowing multi-channel memory, but I'm under the impression as long as the specs (speed, timing, and capacity) are the same, it should work.

 

As a bit of a technical background, DDR-SDRAM (any generation of it) has a 64-bit data channel. Combining these channels increases this to multiples of 64-bits. So in a dual channel memory system, if you have matching RAM modules, turns the effective bandwidth into a 128-bit one. A tri-channel system will increase this to 192-bits. A quad-channel will increase this to 256-bits.

[DildorTheDecent]

14 minutes ago, Windows7ge said:

I do believe it was a feature on some older motherboards. I'm not quite sure if there's any remotely modern boards that support it. Realistically it wouldn't be worth it to develop it with today's systems. If you need more memory bandwidth than dual then quad has you seriously covered. That or if you're seriously just that big of a memory hog and you maxed out your quad memory slot motherboard.

IMCs that support quad channel also support triple channel. As long as your populating the correct DIMM slots to get it to work.

 

Some dual socket processors running in single socket motherboards may also change what memory banks they access. While a single socket processor might prioritise odd slots over even slots. A dual socket processor might take the first four slots and not touch the second four.

 

Memory compatibility is almost always affected primarily by the IMC. Some motherboards however are capable of supporting faster memory setups of  memory through improved memory traces.

[Windows7ge]

2 minutes ago, DildorTheDecent said:

Some dual socket processors running in single socket motherboards may also change what memory banks they access. While a single socket processor might prioritise odd slots over even slots. A dual socket processor might take the first four slots and not touch the second four.

So if I ever decide to take one of my Xeon E5 2670's and put it in my old X79 motherboard it's possible I might find myself putting 4 sticks in the 4 identical colored slots closer to the CPU socket for best performance? That'd be an unexpected event.

[MeDownYou]

1 minute ago, Windows7ge said:

So if I ever decide to take one of my Xeon E5 2670's and put it in my old X79 motherboard it's possible I might find myself putting 4 sticks in the 4 identical colored slots closer to the CPU socket for best performance? That'd be an unexpected event.

Yep exactly that's a quad channel design so filling up those 4 slots will provide with the best rate, filling them all will only increase capacity.

[Windows7ge]

9 minutes ago, MeDownYou said:

Yep exactly that's a quad channel design so filling up those 4 slots will provide with the best rate, filling them all will only increase capacity.

That's worth noting. I've had thoughts of putting the Xeon 8 core in my 2011 motherboard for applications that rely on core count over core clock since the 3930K I bought for it only had 6 cores and the 3960X didn't have more. A CPU that costs 1/3rd the price with two more cores and a 3.3GHz turbo. Sounds worth it to me for high multi-core reliant applications.

[DildorTheDecent]

11 minutes ago, Windows7ge said:

So if I ever decide to take one of my Xeon E5 2670's and put it in my old X79 motherboard it's possible I might find myself putting 4 sticks in the 4 identical colored slots closer to the CPU socket for best performance? That'd be an unexpected event.

I had a 2603v3 recognise slots 1/3/5/7 (red, primary/ASUS recommended configuration) as slots 1/2/3/4 which lead me to believe that those slots would normally be reserved for CPU0.

 

CPU1 would end up using slots 4/5/6/7 which on a Rampage V Extreme are slots 2/4/6/8.

 

Maybe memory controller setups are just different for Xeons since the dual socket ones have their memory banks right beside them.

[Windows7ge]

4 minutes ago, DildorTheDecent said:

Maybe memory controller setups are just different for Xeons since the dual socket ones have their memory banks right beside them.

The only thing I can think of, would be the very small lowering in latency when requesting data from RAM. I could see this making a noticeable difference in the data-center but on a desktop it'd be immeasurable so they just put the default slots on the outside.