Question about Dual Channel Memory

I currently have 2 1gb sticks of corsair XMS2 ddr2 800 memory. (PC2-6400 400Mhz)

Now I would like to know, for me to not be depriving performance in any way, what are my options? I'm a little confused on what I can put into my other 2 memory slots.

Does the memory HAVE to be 2x1gb sticks of 1.8v 5-5-5-18 (or less) ram?
ie Would these work? http://www.newegg.ca/Product/Produc..._DDR2_SDRAM_DDR2_800_(-_-20-211-066-_-Product

Would I be able to install a 2x2gb set in there for a total of 6gb of memory, and still have everything running fine no bottlenecking? That would be 2x1gb in dual channel, and 2x2gb in dual channel... does this work?
ie something like this http://www.newegg.ca/Product/Produc...cm_re=2_x_2gb_ddr2_800-_-20-231-219-_-Product


Thanks!

 

Populating all 4 DIMM can cause problems (I know as I have spent 2-3 days tweaking my BIOS to finally get my 6GB working). I had 2x1GB and bought 2x2GB but when I added all 4 modules the system would just give me BIOS error beep codes. I had to remove 2 modules and then tweak my vMCH and vDIMM until I could get the system to boot with all 4 modules (it would boot with just 2 modules and both "kits" had passed" memtest).

What mobo do you have?

Your going to need to find out your NB Temps (a.k.a. FSB, MCH) if you can for a baseline before you go any further.

You can put in different makes, speeds and timings of RAM but the more variables that are different the more difficult it can become to get the system to BOOT and run stable.

 

I have an Asus M3N-HT Deluxe/HDMI motherboard, with a Phenom II X4 940 AM2+ in there.

What were the variables with the ram you are putting into your system? Same voltages? Same clocks?

Here are the specs of the Adata's and my ram. (Newegg & cpuz)

http://img710.imageshack.us/img710/1706/ram.png

 

So from that mobo we can see that BIOS gives you a lot of voltage control options and you will probably need to increase these to get 4GB or greater to run (vHT I assume and possibly vDIMM):

http://www.asus.com/product.aspx?P_ID=ka4Zc9Wj4y1RINc4&templete=2

The important things that were the same about the kits I used were voltages and the make but my Module timings, size and speeds are different as I wanted a kit for OC runs a bit later (higher speeds mean I can attempt higher FSB) and the 4GB were so cheap.

I am not sure "how" the memory controller pathway works with an AMD but with Intel it passes through the FSB (aka MCH, North Bridge) and tha is what needed to tweak mostly on mine.

Importantly you will only ever get to benefit 6GB in a 64Bit OS (I have XP64) and it is a waste in a 32Bit environment.