My boyfriend has a Sony Vaio desktop that attempts to run Windows XP on 512 MB of RAM. I ordered him the correct 1 GB upgrade kit as two 512 MB DIMMs.

I looked at the motherboard, and it's composed of two banks of two slots each. The existing configuration has one 256 MB DIMM in one slot in each of the two banks.

My question is how I should install the new upgrade to give him 1.5 GB of RAM. I had always thought that identical DIMMs should be installed in all slots of a given bank, not split as his are. Should I just go with what Sony has and put a 512 and a 256 in each bank, or should I move them so that each bank has two identical DIMMs in it? I lean to the former since that's how Sony made it, but I'm not quite sure.

I figure some of the tech gurus here will have an easy answer. Thanks!

It probably has dual channel memory, which will give better performance if the memory is installed in identical pairs in each bank. I would add the two new modules to the empty banks and leave it at that.

If you search for the model number on the crucial site it will let you know if it's dual channel or not, and if you need to fill a bank with the same memory (which apparently you know you don't have to do because it didn't come that way)

Agreed. And even if you just replace the existing RAM, (upgrading from 512MB to 1GB is great) the jump from 1GB to 1.5GB will be imperceptible to the average XP user.

Aha, thanks! Crucial's website was very helpful. So it DOES support dual channel memory but according to Crucial I don't have to install in matching pairs.

So if I understand things, I can just fill in the currently empty slots and be OK - but I will get a performance gain by moving things so each bank is filled with identical DIMMs.

Right?

edit: Crucial's site also says that this model Vaio is four banks of one slot each. Just by looking at the motherboard, it looks like two banks of two slots each but apparently looks are deceiving. So I can just install any RAM I like anywhere, I think.

Take a close look at the markings on the motherboard. Even though you see two banks of two slots, that may not be the way the computer is wired. My computer has:
1------2-------3------4
B1S1 B2S1 B1S2 B2S2

(B=bank, S=slot)

So if you are looking from left to right, the first and third slot are bank 1, the second and fourth are bank 2. Mine are also color coded black-blue-black-blue. Most likely the two existing memory cards are in the same bank.

Not necessarily. I would imagine it shipped in the best possible mode which would be dual channel mode, but we really don't know that from the info we have here.

cpuz or other programs can tell you how your memory is configured on the memory pane. Find it and run it and see what it says. Then you will know what to do or try. (unless you have the manual or other info direct from Sony.)


My Sony FW laptop has 2 DIMMs running in dual channel mode. The SPD pane gives details about each DIMM.

-David

Cool, thanks. I just installed the new RAM, leaving the existing DIMMs where they were, and it makes a dramatic difference in performance. So I'm happy, and he's happy.

I just played with CPU-Z on my laptop - pretty neat little program.