What To Look For When Buying RAM

From the outside looking in, RAM can be one of the most confusing pieces of hardware to buy for a system.  With all the types/sockets, speeds,  placement, and settings available, I can see how it can be a daunting task.  Anyone without experience wouldn’t know what what kind to buy or what is considered a good brand nor be able to properly install it.  The Internet has allowed us to come a long way into doing things for ourselves but some times the subtleties are left out.  After reading through this article, you will be able to tackle buying RAM and have a leg up on the procedures for installing it correctly.

All These Types, What’s The Difference?

When it comes to RAM, there are a lot of choices.  Just take a look at the physical shapes and sizes and you will see some major differences.  Check out the slots on the bottom of the RAM sticks.  Each one is in a different spot.

Desktop RAM:

Laptop RAM:

You will notice that the DDR and DDR2 are very similar in slot placement.  I know of some inexperienced installers who have made that mistake and tried installing a DDR2 stick in a DDR slot and either cause damage to the RAM slot on the motherboard or the RAM stick itself.  This is very handy information if dealing with dirty RAM or RAM that has had its sticker damaged or torn off.  Each motherboard should state what type of RAM it is compatible with as well as it’s max speed.  Check the manual or download it from their company’s website if you are unsure.  A trained tech should be able to tell on sight what a stick of memory is.  Granted there are other sockets of RAM available for older machines, such as RD RAM, but I doubt the majority of readers will come across anything other than that listed above, until DDR4 comes out…

Speed: If You’re Not First, You’re Last.

What is the difference between PC2100 and PC6400?  Basically these numbers on the sticker or in the product listing will give you an insight into how your RAM will perform.  Each socket type has a range in which it functions.  DDR ranges from PC-1600 to 3200, DDR2 from PC2-3200 to 8500, and DDR3 from PC3-6400 to 12800.  Think of the numbers after the “PCx” as the memory’s speed rating.  It directly translates to Megabytes per second as it’s total bandwidth.  What that physically means is, a DDR PC-3200 stick transfers at a peak theoretical rate of 3200MB/s making it faster than another DDR stick of PC-1600 since it’s transfer is 1600MB/s.  So basically the higher the “PC-XXXX” number is, the higher the transfer rate is and the better the RAM is.

Placement Can Be Crucial

As I mentioned in my previous article a Quick and Dirty Hardware Buyer’s Guide, the placement of the RAM physically in the motherboard can make a world of difference when it comes to power consumption and overall speed.  Dual channel memory will only perform if the motherboard has support for the dual channel operations.  When installing Dual Channel memory, assuming the motherboard has more than two RAM slots, you have to consult the manual to see exactly which slots are tied together.  In most new boards, these slots are color coded usually having two blue and two black RAM slots telling your visually which slots to stick your pair of Dual Channel RAM into.  Another thing to look out for is some motherboards have a primary slot or slots.  Old RD RAM boards were notorious for this type of shenanigans, as well as the old Dell’s and their spacer/filler “fake” RAM.  If slot 1 is the primary and you are only installing one stick of RAM in the motherboard, it has to be populated for that board to POST otherwise it will not recognize it has any RAM installed at all.  Granted this was more of a legacy issue, but always good to know especially if working on older systems.

Also, make sure you pay attention when buying or installing RAM into a system when those sticks are of different speeds.  It is best practice to install all of the same types/brands/speeds of RAM when doing an upgrade but sometimes when money is tight and you are only adding some RAM to an existing system, this cant happen.  When that is the case, just realize that all the RAM installed will only operate at the speed of the slowest installed memory module.  This means, if you bought a PC3- 12800 stick to go along with the existing PC3-8000s you have installed, it will not function any faster than the 8000s and it was basically a waste of extra money unless you are planning to upgrade the others soon.

Alternate Settings

This is the optional part of the article and one I will not go into detail with because it can burn up the RAM and motherboard in a flash, literally.  Many motherboards today come with BIOS tweaking programs installed via Windows and allow a great deal of tinkering to be had.  Want to change the CAS latency, frequency, or CPU read delay?  It is all doable and can add significant processing speed for data.  This isnt something you would likely do to increase gaming performance like OCing a CPU or Graphics card but it can help with general data speed.  Old BIOSs were a pain in the backside when it would come to changing anything short of the Boot Order but now days the BIOS is a wonderful location to begin your Overclocking.  Each BIOS is different and each BIOS program as well but they mainly alter the same settings.  You have to be careful to understand what the possible max settings are for your RAM and what your motherboard can supply to the RAM in terms of voltage.   Go over those and you will have some major issues and probable part damage.

Summary

With all the numbers, speeds, and configurations available, one could easily get frightened at the thought of having to purchase RAM.  Now that you know what socket type to look for, you will be able to narrow your possibilities down to what you can afford.  With the additional information on the differing speeds, you can decide how fast you want and analyze your motherboard to see how fast it can handle.  Knowing that placement can cause your new or used rig to function slower or not even POST at all, you can avoid the common mistakes others have made.  Finally, if you are feeling adventurous you can edit your RAM settings and try to squeeze every last once of performance out of your memory.

The best companies I have found when purchasing RAM are Kingston, Crucial, Patriot, and Corsair with G.Skill and PNY close behind.  I base this off of years of use and purchase and mainly on warranty.  If a company is willing to stand behind it’s product for life, you know their quality department is doing a good job or they would be out of business.  Granted sometimes a line slips through the QC gate and is fundamentally flawed like the G.Skill Ripjaws (4GB x 2) did recently.  This is why it is always a good idea to do a  fair bit of research on whichever product you settle on to make sure you are not buying a lemon.

One Response

  1. Rob Walls Dr_Bob May 13, 2013