Not many computer components come in more flavors than memory. Don’t overlook high-density versus low-density requirements when selecting what’s best for your build or upgrade.


If you go into a computer superstore or browse a memory manufacturer’s Web site, the choices for memory can get rather overwhelming. Many people consider only the amount of RAM they want: 512MB modules, for example, or perhaps 1GB or 2GB modules. FSB (front side bus) speed is a consideration. There’s DDR, DDR II, and DDR III. And then there’s ….. and on it goes.

Recently, however, I’ve seen more questions about high-density versus low-density RAM.

Generally speaking, low-density 1GB modules are made with 16 chips, 8 on each side, using 64Mx8 device, while high-density 1GB modules are made with 16 chips, 8 chips on each side, using 128Mx4 device. I’ve actually looked, and not all RAM is actually labeled one way or the other. You might have to look on the chips themselves. I’ve also read that low-density RAM is compatible with 100 percent of the system boards, while high-density RAM is compatible with only 10 percent. And if you use high-density RAM in a system that requires low density, either the system will recognize only half the amount of RAM installed or it simply won’t boot up.

As always, it’s recommended to consult the system board manual or the manufacturer’s Web site for requirements and compatibility. However, I recently upgraded the RAM on an ASUS P4P800 Deluxe system board, going from 1GB to 4GB, and there was no mention at all of high-density versus low-density in the system board manual. High-density RAM is generally cheaper, so that’s what I went with. The system booted up just fine, both the BIOS and the OS recognized all the RAM installed, and the system ran very well, so I suppose mine was among the 10 percent compatible with high density.

I’m still not 100 percent certain of all the ramifications of high- versus low-density RAM — or whether or not what I’ve read is 100 percent accurate. So other than sharing this small bit of information, I suppose I’m simply suggesting it’s something to be aware of.

Oh, and there’s something else I can provide in regards to high- versus low-density RAM. By just mentioning the issue in this blog piece and opening up a discussion with my TR peers, I’m sure all the issues will be clearly addressed.

So please share your thoughts and experiences with high-density versus low-density RAM.