One of the easiest PC upgrades that results in a noticeable improvement in the performance of a computer is a RAM upgrade. But before you purchase that new RAM, there are a few things that you need to consider. Here’s a quick checklist to help you make the right decision.

1. Determine the type of RAM you have. Depending on if you bought a pre-built system from a major computer manufacturer, a built to order, or assembled the system yourself, you’ll need to find the appropriate manual to determine the type of ram in the system. It’ll be either the owner’s manual for a pre-built, like a Dell or HP, or the motherboard user’s manual if you purchased a built to order or assembled the system yourself. Alternatively, you can call or consult the manufacturer’s website or use a program like PC Wizard 2008 (www.cpuid.com). A computer purchased over the past ten years will have either SDRAM, DDR SDRAM, DDR2 SDRAM, or DDR3 SDRAM. If you have original SDRAM in your system, I’d suggest it’s probably more worthwhile to invest in a new PC than bothering to upgrade the RAM. Note that for laptops, you will require SODIMM which is a smaller form of SDRAM. Regular SDRAM for desktop computers will not fit in laptops.

2. Next, determine the RAM transfer rates the motherboard in your system supports. This can be denoted by one of two ways on RAM. It’s either noted by the data transfers per second or the peak transfer rate. Most systems will support multiple transfer rates. It’s probably starting to sound overly technical so let me give an example of what you’re looking for:

DDR2-800 aka PC2-6400

Here, DDR2 tells you that you have DDR2 memory (obviously) with 800 million data transfers per second. Its alternate (module) name is PC2-6400, where PC2 denotes DDR2 (similarily PC3 would denotes DDR3), with a 6400 MB/s peak transfer rate. Any respectable computer shop, be it a retail location or online should be able to provide you with the correct RAM regardless of which naming convention you provide them with.

3. Determine the number of RAM slots in your computer and the maximum ram size (in Megabytes or Gigabytes) each slot supports. Once again, depending on if you bought a pre-built system from a major computer manufacturer, a built to order, or assembled the system yourself, you’ll need to find the appropriate manual to determine the type of ram in the system. I’ll be either the owner’s manual for a pre-built, like a Dell or HP, or the motherboard user’s manual if you purchased a built to order or assembled the system yourself. Alternatively, you can call or consult the manufacturer’s website or use a program like PC Wizard 2008 (www.cpuid.com). You dont want to end up purchasing more RAM modules than your motherboard can support nor do you want to purchase RAM that has a size that isn’t supported.

4. Determine if your computer supports dual channel memory. If your system supports dual channel, you will most want to take advantage of it. Dual channel effectively doubles the throughput rate of the RAM. To ensure that RAM works properly in dual channel, RAM manufacturers sell RAM in ‘matched pairs’. Basically, the RAM modules are tested to ensure that they work correctly as a pair and are sold together as a ‘kit’. You can purchase two single modules of the same brand and model and they may work in dual channel but it would not be recommended. Also, you can use dual channel kits in single channel. You just won’t get dual channel performance from them.

5. Most people at this point would believe that they have enough information to purchase RAM but this can prove to be a big mistake as laptops and newer PCs tend to be more finicky when it comes to RAM. To help reduce chances of incompatibilities (and headache) it’s best to consult the website of the respective RAM manufacturers. The majority them provide their own ‘Memory Configurator’ which helps choose RAM that they have tested and are known to work with specific system and motherboards. I have listed a number of manufacturers below that have this service on their website below:

Buffalo - http://www.buffalotech.com/memory_configurator/BT
Corsair - http://www.corsairmemory.com/configurator/default.aspx
Crucial Technology (Crucial Memory Advisor Tool) - http://www.crucial.com/#
G.Skill - http://newgskill.web-bi.net/bbs/G_SKILL/G_Serch_for_Memory.php
Kingston (Memory Search) - http://www.kingston.com/default.asp
Mushkin (Find Your Upgrade) - http://www.mushkin.com/
OCZ Technology - http://conf.ocztechnology.com/index.php?c=1
Patriot - http://www.patriotmem.com/configurator/index.jsp
Supertalent - http://www.supertalent.com/tools/memoryFinder.php
Team Group - http://www.teamgroup.com.tw/teamgroup/en/service.php
Transcend - http://www.transcendusa.com/Support/Search/index.asp

Once you have a list of compatible RAM, make sure to compare it against the notes that you took in the first four  steps to ensure that they do match up with your results. Note down the manufacturers part number and you should be able to ask the local computer shop if they have stock or are able to bring it in. For most online stores, you should be able to plug in the part number into their search field and hopefully it will pull up the part. One site I know for a fact this works is a site that specializes in memory and also happens to be a sponsor of this site (shameless plug).

 Memory House

www.memoryhouse.com

System manufacturers and motherboard manufacturers provide their own list of compatible RAM under what they call a QVL (Qualified Vendor List) but it’s usually a very limited listing or a list of overpriced RAM that they sell through their own website.

Other important stuff you should know before purchasing RAM

1. If the RAM is also noted as being FB, fully buffered, registered, Error Correcting Code, ECC, or a combination of these words, be very careful as in most cases it’s unnecessary and may not be compatible with your computer. Usually this kind of RAM is for computer servers or computers designed for specific applications.

2.  Some older systems that use DDR or DDR2 memory have ‘density’ limitations. Usually it will be noted in the manual as ‘SS’ (single sided) or ‘DS’ (double sided) in the manual. If a specific slot, or specific slot combinations, requires that RAM be either single or double sided, you’ll need to visually inspect the RAM or ask the supplier. Basically, single sided means that there are RAM chips only on one side of the RAM module and double sided means that there are RAM chips on both sides.

3. If the RAM comes with a fancy metal cover, commonly referred to as a ‘heat spreader’, you need to be careful as well. Often this kind of higher performance RAM requires a higher voltage to operate correctly. Consult the manufacturer’s website for the operating voltage for the RAM. The standard voltages for RAM are as follows:
DDR - 2.5 volts
DDR2 – 1.8 volts
DDR3 – 1.5 volts
The setting for the RAM voltage can be found in the BIOS of the computer usually shown as DRAM voltage or VDIMM.

4. It is not recommended that you mix RAM of different brands. It may work but it is not guaranteed, so consider your self forewarned. Its better just to take out the old RAM and replace it with the new RAM.