An Asus A7N8X-XE deluxe board with dual channel is currently winging its way to me as I speak. One of the features I wish to use are dual channel memory. Currently I have two sticks of Crucial 512MB PC2100 memory EXACTLY the same - when ordering for my ECS motherboard I could only find these modules as single modules so I simply bought two of these modules. My ECS motherboard only supported 1GB total and had two DIMM slots. Plus my wallet couldn't stretch that far

Would I be able to use these previously separately bought modules to achieve 1GB of RAM in a dual channel setup with my Athlon XP 2000+ or do I have to purchase the memory in those pre-packaged dual channel pairs that they sell them in

Also, if I was to use a AMD Athlon XP 3200+ processor, can I still keep my PC2100 memory and use it with the processor in dual channel until I can afford to upgrade the memory to PC3200.

Last question

Can dual channel work with the following setup:

Athlon XP 2000: 2x512MB Crucial PC2100 RAM+ 1GB PC2100 RAM
Athlon XP 2000: 2x512MB Crucial PC2100 RAM + 1GB PC3200 RAM
Athlon XP 3200: 2x512MB Crucial PC2100 RAM + 1GB PC2100 RAM
Athlon XP 3200: 2x512MB Crucial PC2100 RAM + 1GB PC3200 RAM
Athlon XP 3200: 2x1GB PC3200 RAM + 1GB PC2100 RAM

Let me know your thoughts on this :? I am not that familiar with the effective use of dual channel. (I hear those "NOOB" crys again! )

Thank you for your time

You don't need matched pairs. Normally, the 2 x 512mb you have now will be fine. You'll need to lower the multiplier to get the RAM to run at PC2100 speeds and there is no reason why it wouldn't run async with the processor. Anyway, you would find dual-channel on those sticks at DDR266 speed would possibly be slower than single-channel on DDR400.

Dual-channel is hugely overrated, especially on NForce 2 chipsets, so I really would ignore it if I were you. Performance gain is 0-2%. It is more beneficial on high-bandwidth chips like Pentium 4s and Ds, but on the Athlon XP it's not a big concern. So I say, go with more RAM totally (i.e. 2Gb in all) and ignore dual-channel mode. The extra RAM easily outweighs dual-channel.

That was what I was hoping to achieve in the long run once I can afford it - The motherboard has three slots so I was hoping to have 2GB in dual channel and once I upgrade to vista (an OS which supports and can effectively use more than 2GB of RAM) I will add in another stick of 1GB to fill the motherboard to full steam - a 3200+ processor and 3GB of memory, along with my current rig of graphcis card, sound card etc, should be plenty to run vista with the new aero interface right?

I understand that I will get a slower speed with my 3200+ while using PC2100 RAM - when I switched to my ECS board I originally had 768MB of SDRAM - this worked with my AXP 2000+ although it only ran at 1.25ghz. Then when I could afford 1GB of DDR I added it straight in and gave the 768MB to my sister's Duron 800 As long as the PC will work smoothly until I can get the faster memory that will do me for the time being.

If I was to buy the PC3200 memory before I upgrade the processor could I use it with my AXP 2000+ albeit at the slower PC2100 speed?