3 Replies Latest reply on Apr 25, 2016 10:45 AM by allan_intel

    difference between single and multi channel memory


      hello. My question is in regards to potential laptop performance. Please forgive my ignorance in advance for most of this is quite new to me.  I am wanting to upgrade the ddr3 ram in my laptop and also have an 850 Samsung ssd installed. My first question is this.  What is the difference between single channel memory and duel channel memory?  I ask because I was told my new laptop has single channel. 8 gigs of ddr3 to be exact.  I have little doubt that I will see some  performance increase with a ssd upgrade however due to my lack of understanding with certain aspects of computing I'm very unsure of the memory upgrade.  My system specs are the following.  amd fx 8800p w/8 gigs system memory.  1 tb hd. r7 intergrated gpu and an r9 385 gpu 4 gigs ddr5 memory.  model is a Lenovo y700 available only at best buy.  Also I was told it has an m.2 slot for a m.2 ssd but it will not be reconized by the system due to Lenovo not providing the traffic lanes for it to work whitch is what made me decide to go with the sata type ssd. Last I was told to go with 1600 ddr3 stick and not the 2133 stick because again even though the computers cpu will work with it for reasons unknown to me it will also not recognize it pretty much being a waste of money.  Any insight would be extremely helpful. thank you  doug.

        • 1. Re: difference between single and multi channel memory

          This is the information for computers with Intel(R) chipsets: Single- and Multichannel Memory Modes

          Please bear in mind you are using AMD chipset; therefore, the information may vary.



          • 2. Re: difference between single and multi channel memory

            From what i have seen in traditional computing. Memory, or DIMM Slots work in parallel. It may differ slightly being in a Lap top but overall i found it to be like this. A single channel memory architecture is composed of two Slots. 1 Active channel contains a Max of two banks. Each slot works side by side on 1 channel to store and buffer data. With this in mind, that means Dual channel architecture contains 4 Memory banks, Quad channeling contains 8 memory banks.


            The 1st Dimm in each channel will determine the clock rate of the system bus. The second dimm in each channel allows for more addressing and buffering space. So to have a dual channel system, you need at least 2 memory modules. For quad channeling, you need at least 4 memory modules. Single channel minimum requires 1 memory module, In this case 1 stick of DDR3. The clock of the memory module is also determined by the CPU's memory controller.


            The prime benefit of a multi channel memory Architecture is increased memory bandwidth. A higher memory bandwidth allows for faster Read and Write operations in traditional computing before needing to access the HDD via the paging file. Also as a result, you end up with more Buffering space due to the additional memory modules.


            One stick of DDR3 1600 should have a theoretical max bandwidth of 12.8 Gigabytes of I/O bandwidth per second. This is calculated by multiplying the base clock of 1600MHZ X 8 bits. 8 bits being 1 byte of data. So single channel DDR3's memory bandwidth is 12.8 Gigs, Dual channel is 25.6 Gigs and quad channel is 51.2 Gigs of memory bandwidth respectively per CPU compute cycle.


            Increased memory bandwidth will achieve faster computing results in applications that are written to take advantage of them. Heavy multi threaded apps are a plus, as well as some video gaming engines. The CPU and motherboard are limiting factors on Multi channel architecture as well as memory operation clocks, the HZ frequency.

            • 3. Re: difference between single and multi channel memory

              Great information GreeneMan, thank you.