only two banks dual channel?

I bought an ASUS M3A79-T Deluxe motherboard. I happen to have four matching 1 GB sticks of Corsair XMS2 memory in my spare parts box. When I read the ASUS users manual I discovered that only two of four memory banks (DIMM slots) are dual channel. The other two memory banks are single channel. In addition the manual recommended installing only 3 GB of memory for Windows XP Pro because the OS will only recognize 3 GB.

What do you think? Should I follow the manufacturer's recommendation and install only 3 GB of memory? Is there any benefit to installing 4 GB of memory? Are there any other options?
 

I wonder why a highend AMD 790FX motherboard would only have 2 RAM slots that operate in dual channel mode?
After all the 780G motherboards have no problem with 8GB RAM running dual channel mode in four RAM slots.

And why does the Asus website claim the M3A79-T Deluxe supports:
"4 x240-pin DIMM, Max. 16 GB, DDR2 1066/800/667 Memory Dual Channel memory architecture"



Either the website is wrong - or you have less than stellar manual reading skills.
 
crowheart27us,

Yes, I could simply purchase two 2GB sticks of memory for use in dual channel mode. I am building a pc from spare parts that I have. All I purchased was a new CoolerMaster 932 HAF case, a few minor parts for a case mod, and a motherboard.
 
WR2,

I don't know either. Here's what's in the owners manual:

"You may install varying memory sizes in Channel A and Channel B. The system maps the total size of the lower-sized channel for dual-channel configuration. Any excess memory from the higher-sized channel is then mapped for single-channel operation."

I'm thinking "lower-sized" means Channels A1 and B1 (yellow banks) and "higher-sized" means Channels A2 and B2 (black banks).

The manual also recommends installing memory in the yellow banks for better overclocking capability.