What is dual channel?

[wiky123]

what is dual channel? what benefit will I get by plugging 2 RAMs instead of 1 RAM on dual channel supported Motherboard

 

[4745454b]

http://en.wikipedia.org/wiki/Dual-channel_architecture

Ask about things you didn't understand please.

 

[COLGeek]

See here: http://en.wikipedia.org/wiki/Multi-channel_memory_architecture

The difference for most users is not even noticeable except under extreme conditions.

 

[Shaun o]

Basically, memory in single channel mode say if you have only one memory stick in the memory slots of your motherboard.
Is 64 Bits of data wide, meaning it can only send 64 bits of data per every clock cycle or request from the cpu to access the memory module to read and write data.

With dual channel mode you are adding the bus width or the amount of data that can be written or read by your cpu.
each clock cycle of data blocks would be 128 bits of data per clock cycle.

So it takes less requests from the cpu to obtain a large amount of data.
64 vs 128 bit means double data rate or dual channel mode.
And takes less time and memory clock cycles to get the same amount of data requested by your cpu from and to the memory.speeding things up. with 64 bit it would take two requests from the cpu to obtain 128 bits of memory data.
Where as only one cpu request to get 128 bits of data in a single read or write to memory pass.

 

[wiky123]

well,that mean buying 2x4GB is better than 1x8GB RAM with same bus speed?

 

[4745454b]

Note that this doesn't make the computer twice as fast. Just the memory read/write operations. You generally see 5-10% improvements in speed overall. IGPs tend to see a lot more thanks toe dual channel and if you are using the IGP then you should be using dual channel to get the best speed from it.

 

[Shaun o]

2x4gb stick spot on.
Yep because it will enable dual channel memory mode.
And 128 bits of data per memory clock cycle.

Think you have the idea now.
It does not double again Btw if you have, or had 4x4gb stick of memory in four memory slots of the board. it will still be 128 bits wide ok.
Only if you have a quad channel capable motherboard. will double to 256 bits of data per clock cycle.
Anyway hope it helped you understand how it all works.!

 

[Tradesman1]

While the 64bit vs 128bit is accurate, dual channel (the 128 bit) is different from 'dual' data rate mentioned above - DDR is DOUBLE data rate so if the true freq of a stick is 800 then as DOUBLE data rate you take true freq 800 x2 = 1600 effective. It runs at this data rate regardless if it is in single, dual, tri or quad channel mode, In dual channel mode instead of each stick being seen as an individual 64 bit device, the MC (memory controller sees all the DRAM as a single 128 bit device, which would theorectically double the bandwidth, but in actual practice will provide upwards of a 10-15% performance gain

 

[4745454b]

Correct. You'll see a slight improvement in speed with 2x4 instead of 1x8. Note that running 4x4 does NOT give you quad channel. Unless you are on a few select systems. It's still dual channel, just with two sticks on each channel instead of one. There is a tri channel, but Intel only had a few systems that used it.

 

[wiky123]

thank you all for giving me a clear idea