DDR2 RAM channels

Forgive me if I'm wrong, but I seem to remember that when you add RAM, if you want to take advantage of the dual-data rate speeds (DDR) then you need to populate the sockets in pairs. Now, in the stock 512MB AA1, there's the equivalent of one 512MB module soldered on the mainboard, in which case (if my theory is correct) one would need to add another module of the same size in order to get a total of 1GB operating at full dual-channel speeds. Adding a 1GB module to bring the total up to 1.5GB will result in the DRAM running in single-channel mode because of the different module sizes.

Now, of course it can be argued that for some users 1.5GB at single-channel speeds is preferable to 1GB at dual-channel speeds, but apart from that, I think achieving the full DDR2 speed would be quite a useful performance boost and certainly one that I would be interested in obtaining.

Has anyone who has upgraded with a 512MB (rather than 1GB) module been able to determine whether your RAM is working in dual-channel mode?

The only way I could determine this was to use Windows XP (once I'd NLite-ed it, and shrank the Linpus partition to make room), and then run PC Wizard ... it shows my original 512MB in single-channel mode. I don't know if there's a way to check this from within Linpus, but the chipset is reported as supporting dual channel DRAM.

 

Right idea, wrong terminology...the dual in DDR means it transfer data on both edges of the clock signal. Dual channel is what you are thinking of.

This is something I've always wondered about with laptops...since most of them usually ship with a free slot, does it mean most are running in single channel mode? I don't know the answer, but my guess is yes.

But, here are some interesting tests that show the theoretical gains of dual channel not adding up to a lot of real-world gains in most cases.

And that's with a 3GHz Core2 Duo, so I can't imagine our little Atoms being able to tax the bandwidth of DDR2 in single channel mode.

 

Just to let folks know, I added 512MB and no, it doesn't work in dual-channel mode. You might as well fit a 1GB module if you're going to go to the trouble ... I just wonder if 1GB draws more power than 512MB, thus potentially shortening the battery life?

 

1GB module does use slighty more power, but I don't think it affect battery life much

 

Your theory is right; dual-channel should improve the performance of a computer. But in real life situations, dual-channel configurations only provide a little bit of improved performance. Plus, the Atom isn't a powerful processor either, so, dual-channel would be pretty useless.

Anyway, no, the AspireOne does not support dual-channel. It'd be pretty pointless.