Dual Channel RAM Question

[magicman]

I'm pretty sure this wasn't answered in the RAM 101, forgive me if it was.

I'll be soon upgrading to Dual Channel DDR400, but I've got 2 sticks of 512MB Single Channel that i don't want to get rid of (my aim is to turn off the page file). If I have 2 slower single channel modules running alongside 2 faster dual channel modules, how with the system handle it?

What I really mean is, will the slower modules slow down the whole system? Or will the system focus on the faster modules? I take it RAM timings will have to be the same across the board, so will it be that 2 thirds of data is written and read from the faster modules?

 

[ghost]

Yes your system will run as fast as the slowest components in there ! If you have 2 PC3200 in dual channel and 1 PC2700 aside of them they will all run at PC2700 speeds, If you change it in the BIOS to run asfast as PC3200 you could damage your system ! You could put a divider on the CPU/RAM speeds to OC the CPU, But the RAM will still be slower !

I would try to get the same type of RAM you have running in dual channel then add them !, But if your a gamer or some1 who will use the most out of there PC i would sell the 2x 512 sticks and buy a 2x 1GB Dual channel kit !

 

[magicman]

I'm not sure you understand, I have PC3200 (DDR400) RAM installed at the moment, the only difference is that they are Single Channel. So what I would be changing to is 2 x 512MB DDR400 (PC3200) Single Channel + 2 x 1024MB DDR400 (PC3200) Dual Channel. DDR333 doesn't even come into it.

 

[ghost]

sorry lol thats mornings for ya LOL, I think there are issues with adding RAM on top of RAM in dual channel due to the memory controller ! i have even heard of ppl losing performance due to this ?

I don`t know enough about it to answer the question ! you be better off waiting for a 2nd opinion.

EDIT: Just sopke to some1 about this and they said

"Yes, the bus widens to 128-bit in Dual channel mode. (In reality, you get twin 64-bit memory controllers working in parallel.)

On an Athlon 64 machine, you really need to use either a matched pair of sticks or two matched pairs. I believe it's possible to run dual-channel with only three sticks (as often done on nForce2 Socket A systems), such as a 512Mb stick in one channel and two 256Mb sticks in the other (making 512Mb available to each channel), but I've not done it and I doubt it's very robust (if possible at all)."