Quad Channel? Dual Channel? Whaaa?

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Jul 22, 2018
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Someone mentioned something about quad channel motherboards and compatibility issues with a 4x4gb memory setup, he did not go into much detail abd left me rather confused. I already have 2x4gb sticks and wanted to purchase two more, does anyone see any issues with the build I have listed below?

https://pcpartpicker.com/list/CJvQGG
 
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Nope. Sorry to disagree. Quad channel ram uses different controller chips to accommodate the bandwidth changes and 3 other controllers. Quad channel won't work on dual channel mobo's, same as dual channel won't work as quad channel on a quad channel mobo. The actual ram chips are the same, just the instructions in the controller chip are slightly different. The only time a quad channel kit is the same as dual channel is if the controller instructions are written for that. With a 4pack kit of dual channel ram, if any single ram fails, it can easily be replaced by another dual channel ram stick. If a quad channel ram stick fails, you'll need to replace all 4 sticks unless you have spares laying around since quad channel ram is not sold in...


Could someone explain to me the difference between dual channel, and quad channel? And will either or have an impact on performance for any other component?
 
Your board only supports a DUAL Channel setup and your performance will be just fine IN TERMS OF ALL THE HARDWARE with the selected 4x4 modules.


https://www.pcworld.com/article/2982965/components/quad-channel-ram-vs-dual-channel-ram-the-shocking-truth-about-their-performance.html
Here's a nice article that explains it for future reference.

 


Single, dual, triple, and quad channel memory architectures describe the number of independent memory channels connected to a single CPU or memory controller.

When a system has two active memory channels the peak memory bandwidth is twice that were it to have only a single active memory channel with all else being equal.

When a system has four active memory channels, the peak memory bandwidth is four times that were to to have only a single active memory channel with all else being equal.
 
Your mobo supports only single and dual channel ram.
So 1 stick = single channel.
2 sticks = 2x single channel or 1x dual channel depending on slots used.
3 sticks = 1x dual channel + 1x single channel.
4 sticks = 2x dual channel.

Your ram is rated at single/dual channel. Even on a motherboard that supported quad channel, it'd still only run in dual channel mode. Quad channel ram is quite different and only bought in kits of 4/8, dual channel can be 1,2 or 4 stick kits.

Just because the mobo has 4 ram slots doesn't mean it's quad channel, just means it has 2 sticks for A and B channels each, so 2 sets of dual channel.
 


The ram is identical.

The only difference between a kit of 4 DIMMs marketed as "dual channel" and a kit of 4 DIMMs marketed as "quad channel" is the writing on the package.
 
Nope. Sorry to disagree. Quad channel ram uses different controller chips to accommodate the bandwidth changes and 3 other controllers. Quad channel won't work on dual channel mobo's, same as dual channel won't work as quad channel on a quad channel mobo. The actual ram chips are the same, just the instructions in the controller chip are slightly different. The only time a quad channel kit is the same as dual channel is if the controller instructions are written for that. With a 4pack kit of dual channel ram, if any single ram fails, it can easily be replaced by another dual channel ram stick. If a quad channel ram stick fails, you'll need to replace all 4 sticks unless you have spares laying around since quad channel ram is not sold in single sticks. Chances of incompatability are extreme with swapping out quad channel sticks.
 
Solution


You know what I really love about posts like this? I get to tear them apart.

Quad channel ram uses different controller chips to accommodate the bandwidth changes and 3 other controllers.

There are no controller chips on the DIMMs themselves. There are SDRAM chips and a serial EEPROM. Registered and buffered memory will have a register or buffer chip as appropriate.

Quad channel won't work on dual channel mobo's, same as dual channel won't work as quad channel on a quad channel mobo.

Yes it will. DIMMs have a standard pinout for each generation. This information is publicly available on JEDEC's website.

The actual ram chips are the same, just the instructions in the controller chip are slightly different.

There is no controller chip. If you think that there is a controller chip please post a photograph of one. I will be more than happy to tell you what it really is.

The only time a quad channel kit is the same as dual channel is if the controller instructions are written for that.

Again, there's no controller chip. Please stop making stuff up. The only difference between a dual-channel kit and a quad-channel kit is the writing on the package.

With a 4pack kit of dual channel ram, if any single ram fails, it can easily be replaced by another dual channel ram stick.

If a DIMM fails, it can be replaced with any DIMM of the same memory generation (eg, DDR3) and same IO configuration (16x4-bit, 8x8-bit, or 4x16-bit per rank). If there's a conflict between the configuration information encoded on the SPDs the user may have to configure the memory manually for optimal performance.

If a quad channel ram stick fails, you'll need to replace all 4 sticks unless you have spares laying around since quad channel ram is not sold in single sticks.

There's no such thing as a quad channel ram stick. If a DIMM in a quad channel computer fails, it can be removed and the system will run in either triple channel (4 DIMMs) or quad channel + triple channel (7 DIMMs). It can also be replaced with any other DIMM of the same generation and IO configuration.

Chances of incompatability are extreme with swapping out quad channel sticks.

They are not. The whole purpose of JEDEC specifications is to maximise interoperability. Samsung SDRAM, Micron SDRAM, and Hynix SDRAM will all play well together at the same time. When vendors tighten timings, increase voltages, and crank up data rates it's usually a good idea to install like memory throughout but this is by no means a strict requirement.

When JEDEC standards are observed throughout, memory incompatibility is extremely rare.

Go ahead, reply.
 
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