Clarify dual-channel DDR?

I was hoping someone can shed some light on some dual-channel DDR questions on a K7N2 Delta-L board. My understanding is that for dual-channel to work, you simply put one stick of RAM in slot 1 and another stick in slot 3.

1) Do the two sticks have to be the same amount of RAM, brand, or DDR type (e.g. can it be one PC2700 and one PC3200)?

2) What happens if there are sticks in all three slots? Will 1 and 3 be dual-channel, while 2 is regular?

I went from having 1 gig of PC133 RAM in my old system to 512 megs of DDR400 RAM in the new one, and the slowdown is ridiculously obvious in general OS speed and Photoshop processes. I'm not going specifically for dual-channel, but I'm curious as to what it entails since I'm going to be picking up another stick anyway.

Thanks,
m19

 

For memory to operate in dual channel mode, your mainboard must support it. It appears yours does not. Typically, boards that do have 4 memory slots, and memory must be installed in matched pairs in specific pairs of slots-- usually color-coded for reference. DDR (Double Data Rate) is not the same thing as Dual Channel. Your slow performance may be the result of BIOS memory settings not being matched to the particular RAM you have installed.

 

Further reading indicates your board will indeed operate dual chanel with matched pairs in slots 1&3 or 2&3. On my system, dual channel operation is possible with matched pairs in slots 1&2, or 1&2 AND 3&4, and an odd number of sticks will disable dual channel operation. So, can't say for sure how yours will operate with 3 sticks. But the memory timing BIOS setting idea is worth investigating.

 

I was just about to correct you, then read your second post. The reason I'm asking about dual-channel in the first place was because I knew my board could do it. (I know DDR and dual-channel are different. ^_^)

I had the same thoughts about checking the BIOS settings. The last time I installed RAM was over a year ago so I'd had my settings set, and since this is a whole new board, it's defaulting to Auto right now. I'm going to check those tonight. Would you have any suggestions in regards to settings for the RAM? It's a single stick of Geil DDR400, and like I said the BIOS settings are all auto. I don't necessarily want to overclock it, but I'm not sure what they *should* be set to normally.

m19

 

It looks like the BIOS set the memory to 2.5-8-4-4 automatically. I found a couple sites that suggested 2.5-6-3-3 would be best. I know 2.3 is the CAS, but I'm not sure what the other three numbers are. I've changed it to 2.5-6-3-3 in the meantime to see how that goes.

m19

 

Could it have anything to do with my CPU? Currently I've got a 1.2 Ghz Tbird with the board set to a fsb of 133. Would that affect memory settings at all...?

m19