Hardware Reference
In-Depth Information
Adding the wrong modules to a system can make it as unreliable as leaving a defective module
installed and trying to use the system in that condition.
Note
Before upgrading an older Pentium (P5 class) system beyond 64MB of RAM, be sure your
chipset supports caching more than 64MB. Adding RAM beyond the amount supported by your
L2 cache controller slows performance rather than increases it. Pentium II and later
processors, including the AMD Athlon, Duron, and Sempron families, have the L2 cache
controller integrated in the processor (not the chipset), which supports caching up to 4GB and
beyond on most newer models.
Purchasing Memory
When purchasing memory, you need to consider certain issues. Some are related to the manufacturing
and distribution of memory, whereas others depend on the type of memory you are purchasing.
Suppliers
Many companies sell memory, but only a few companies actually make memory. Additionally, only a
few companies make memory chips, but many more companies make memory modules. Most of the
companies that make the actual RAM chips also make modules containing their own chips. Other
companies, however, strictly make modules; these companies purchase memory chips from several
chip makers and then produce modules with these chips. Finally, some companies don't make either
the chips or the modules. Instead, they purchase modules made by other companies and relabel them.
I refer to memory modules made by the chip manufacturers as first-party modules, whereas those
made by module (but not chip) manufacturers I call
second-party modules
. Finally, those that are
simply relabeled first- or second-party modules under a different name are called
third-party
modules
. I always prefer to purchase first- or second-party modules if I can because they are better
documented. In essence, they have a better pedigree, and their quality is generally more assured. Not
to mention that purchasing from the first or second party eliminates one or more middlemen in the
distribution process as well.
First-party manufacturers (where the same company makes the chips and the modules) include Micron
(
www.crucial.com
), Infineon (formerly Siemens), Samsung, Mitsubishi, Toshiba, NEC, and others.
Second-party companies that make the modules (but not the chips) include Kingston, Viking, PNY,
Simple Tech, Smart, Mushkin, and OCZ Technologies. At the third-party level, you are not purchasing
from a manufacturer but from a reseller or remarketer instead.
Most of the large manufacturers don't sell small quantities of memory to individuals, but some have
set up factory outlet stores where individuals can purchase as little as a single module. One of the
largest memory manufacturers in the world, Micron, sells direct to the consumer at
www.crucial.com
.
Because you are buying direct, the pricing at these outlets is often competitive with second- and third-
party suppliers.
Considerations in Purchasing DIMMs
When you are purchasing DIMMs, here are the main things to consider:
• Do you need SDR, DDR, DDR2, or DDR3 versions?
• Do you need ECC or non-ECC?
