I was at a local computer shop yesterday looking for a used memory card for my desktop. Most of them I looked at had a single layer of chips, but one of them had double-layered chips all the way around. They both had the same specs, the only difference being the double layers. My question is, would anyone know what the difference is? Is one type probably older?
When you say double layered, do you mean on both sides of the circuit board? This is typically referred as, wait for it... ... double sided RAM! RAM modules (often called "sticks") can be the same capacity but one is single and the other double sided. Let's use 2GB RAM modules as an example. Single sided 2GB RAM will use 8 x 256MB chips for 2048MB or 2GB total while double sided 2GB RAM modules will use 16 x 128MB chips. The 8 256MB chips (ICs or integrated circuits) on the single sided are higher density so generally cost more than 128MB chips. So single sided memory modules, as a general rule, cost more than double sided of the same size. There are exceptions, but that's generally the case. That does not automatically mean single are better or faster, however. The same idea applies to sticks where there are two rows of chips on a side. Each chip is of smaller density (fewer "gates" or transistors per chip) than equal sized sticks with fewer chips. But as suggested by these images, two rows on the same side are not very common. There are several different types and capacities of RAM modules. If you are looking to add RAM to your computer, you need to ensure your motherboard will support it. Easiest way to do that is to visit your motherboard's webpage and look at the QVL (qualified vendors list) for supported RAM, or visit one the major RAM makers sites and run their memory wizard/advisor. The Crucial Memory Advisor is very good and will tell what type and size RAM your motherboard will support. You don't have to buy Crucial or from the Crucial site, but if you do, Crucial guarantees suggested RAM is compatible.
Hi Bill. The one I looked at was like the one in attached picture. Do you know if this type of design is older, or if it's better or worse than single layers on both sides? ~ Removed Copyrighted Image ~
Again, not sure what you mean by "single layers on both sides". There are no "layers" on RAM sticks. If there are 8 more chips on the other side of the stick in your image, that is double-sided RAM. If there are no chips on the other side, it is single-sided RAM. And I already noted that single or double is not an indication of quality (better or worse). There are too many other factors involved, including the speed of the RAM. As far as that particular RAM is concerned, I don't know what it is. It does not have any notches on the sides as common DDR 2 or DDR3 RAM modules do.
