Mixing paired memory

[jardenp]

I read through the FAQ for this forum and was not able to figure out the answer to my questions.

Question 1: I am upgrading the memory for some computers at work that will become hand-me-downs. They are all Dell Dimension 4700s. I bought 2GB DDR2 PC2-6400 chipsets (2x1GB) for some of them. There are four slots on each motherboard. If I put the new 6400s in slots 1 and 2, would it improve performance to put the old ones (DDR2 PC2-3200, 256MB each) in slots 3 and 4? Specifically:

Can the pairs run separately?

Would the pairs both run in dual channel mode?

Would the slower chips slow down the new chips?

I guess I don't too technical of an answer, so, in short, what would you do?

Question 2: I'm not sure how much speed is added by dual channel, so would it be better to run 4 identical PC2-3200 chips at 256MB each or a single PC2-5300 chip at 1GB?

Thanks!

 

[o1die]

Slower pair will slow down the faster pair.
Both pairs will run in dual channel mode, but the speed and size differences between the pc2-3200 and pc6400 ddr2 may be too great for them to work together (old motherboard chipset may not work with pc6400, but try it anyway). Check the dell motherboard specs for the 4700; it might run better with slower pc5300 (667) sticks. If necessary, use only the pc6400 and don't reuse the older sticks.

 

[jardenp]

Thanks for your reply o1die. If the slower pair will slow down the faster pair, I'm not even going to bother to only add half a GB of slower memory.

I'm also going to just use the 1GB stick instead of the four 256MB sticks. For what these computers will be used for, they don't require much performance.

Thanks again! It's always nice to have your first question on a board answered quickly!