I know there are many topics related to it, but i am bit confused.
1. Do we have to use two set of memory(RAMs) for it?
2. can a single RAM (memory ) will run on a dual memory architecture?
(1) You can mix and match memory sticks, but they'll only run as fast as the slowest one.
(2) You can run one memory stick, but it will only run at half speed. DDR SDRAM (Double Data Rate Synchronous Dynamic Random-Access Memory) works, basically, by combining the speeds of the two memory sticks to work in synchronization. For instance, I run 1600MHz RAM in my computer, if I took out the other sticks, my single RAM stick would only clock at 800MHz. If you want to go into more detail try doing some Google searches on "DDR SDRAM" and also take a look at the Wikipedia article.
Each channel manager can address (access data in) one stick at a time.
Two (Dual) channel managers can access two modules simultaneously.
Two equal RAM modules of identical specifications, will allow the memory managers to run at optimum performance.
Depending on what your motherboard's manual has to say, you may be able to use differing specs and sizes, 1,2,3, or 4 modules and so on.
But often it will perform at the specs of lowest common denominator between differing modules.
And at last, portions of the differing RAM may be accessed in single channel mode.
At worst case.. accessing even the worst performing RAM configurations is still on the order of a thousand times faster than going to the hard drive.
Single channel - the DRAM runs as a single 64 bit device - in dual channel the sticks operate together as a SINGLE 128 bit device - Does it DOUBLE the speed and performance - NO - you may see up to a 10-15% performance increase - and it's never a good idea to mix DRAM - even if the same exact model - it can and often is problematic - we get requests every day from people mixing DRAM and having problems with it - why people keep telling others that it's perfectly fine to mix - I don't know - yes you might get lucky and get some that will play - but if you don't the time and the expense to correct all often far exceeds what it would have cost just to buy one set with the full amount of DRAM you want