by Terry E. Mercer (c) 1997-1999
What Many Salespeople Tell their Customers:
When the customer asks about RAM - what, where, when, why, and how is there a difference... most sales people do one of three things:
FACT: There are different types, different speeds, and different tolerances allowed by different manufactures.
Generally, you want 60ns (Nano Second) EDO SIMMs (Single In-line Memory Module) or DIMMs (Dual In-line Memory Modules) which have become the industry standard for Socket 7 (standard Pentium) motherboards. With the Pentium II systems - you want the 6ns (yes, 10 times faster) PCI 100 (100Mhz bus path capable) RAM. There is also PC 133 RAM for the PIII's and AMD K7', but make sure that you have a motherboard capable of handling the speed differences before you spend your money there.
EDO means: "Extended Data Out" RAM; this is a special type of RAM which improves the overall performance by overlapping certain internal operations; an average of 5 to 20% increase in speed, where the RAM is concerned. Buy either name brands or purchase from a company you trust. There are both quality RAM, and generic chips. Some of the generics are great and as good as the name brand stuff, others aren't even close. I personally don't recommend buying RAM without knowledge of your motherboard and it's settings and requirements. Matching the RAM with the motherboard & CPU is important - and directly impacts the speed of your system.
With SIMMs, there are different types of chips. Both Parity and Non-Parity, 30, 32, 36, and 72 Pin (72 is now the predominate and most common - even IBM, AST, Packard Bell, and Compaq are now using these). If that isn't complicated enough, there are also 2, 3, 8, and 9 chip SIMMs... 8 is (as far as I know) always non-parity, 9 (same disclaimer) always parity... 3 can be either, but is usually parity. By and large, XT's through 486's require a parity chip, Macintosh's and newer Pentiums do not.
In addition, some motherboards allow you to mix EDO and non-EDO, others automatically drop all the chips down to the fastest speed of the slowest chip. Some motherboards have special settings in the BIOS which allows a technician to "tweak" the settings and make the new RAM faster. Changing from 70ns to 60ns will pick up about a 6 to 12% increase in speed. Going from standard to EDO RAM will gain about another 10 to 20% increase.
DIMMS (Dual In-line Memory Modules) are new, many mother boards made in 1997 to present have the special 168 pin sockets. The PCI 100 RAM came available to the public market mid-1998. They are faster, better, nicer, and significantly dropping in price because of demand. DIMMs have become the standard. If you are one of the few that need to have 64 MB or more RAM in one computer, and your only choice with 128 MB up to 1 Gig of RAM on a single computer, then you will have to get aquatinted with DIMMs. This standard should easily hold for another 1 to 3 years. I, personally, can hardly wait until "flesh RAM" (a cellular based - "live" RAM, which has been in the testing field for nearly 10 years, will some day replace RAM as we know it today).
If you find this confusing, ignore it... and get a good tech to help you. Just remember to buy the RAM from the same company you buy the Motherboard and CPU (then it is their responsibility to insure compatibility). If this isn't possible, try to gather as much information about the motherboard requirements as possible, and the internal components and expansion capabilities of your computer; this will help you (and your technician) in the future.
Important NOTE: Some companies release RAM marked at a specific speed - for sake of example, let's use the PCI 100 screamers of today, which are 6ns. These companies mark the chips at 6ns, as the FASTEST the chips were tested at, plus or minus 10%. Other companies mark the chips exactly the same representing the SLOWEST any of the chips were tested at. Me, I want to get RAM which has the slowest chips at 6ns... because the rest of the chips are probably faster by 10 to 20%. The difference may be $.25 to $5 per megabyte, depending on the company, the type and level of testing and the name on the chips.
Cheaper is not always better, and RAM is usually too important to scrimp on. Also, get the fewest chips possible... 2 SIMMs chips (a pair) is the minimum, whereas you can place DIMMs individually. If you want 32 MB of RAM, a computer store may attempt to dump 8 - 4 MB chips on you, when 2 - 16 MB chips would give you expansion capability that the 8 chips can't, and 1 32MB chip would really be the best. Most motherboards are limited to a specific number of slots - usually 4,6, or 8 on SIMM boards and 2,3, or 4 with DIMMs. The store may save $20.00 or more in giving you the smaller, less popular, close to being discontinued chips, which you will have to throw away, give away, trade-in, or otherwise take a financial loss on in the future if you want to upgrade your RAM memory in the future. This is a common trick many retailers pull, and one to be aware of (some retailers don't think about it and don't really care how you spend you money).
Copyright © 1993 through 2000 T.E. Mercer and PBG, All rights reserved.