I need more memory!
By Parrish Reinoehl, Pathfinder Networks
October 2005
Frequently we are asked by our customers to upgrade the RAM (Random Access Memory) in their PC’s. These customers know that increasing the amount of RAM in their system can help to dramatically speed up the PC. While Windows 98 was quite content with 128mb of RAM and performed great with 256mb, Windows XP is much happier with 512mb or more. The difference in going from 256mb to 512mb can be quite significant when you are talking about Windows XP.
Many times a customer will visit us at our store wanting to get a price to upgrade their RAM or they want to buy a memory module so they can do the upgrade themselves. Many times the customer does not know which type RAM they require or that there are even different types of RAM. Many customers think a memory upgrade is a memory upgrade, nothing special. The reality, however, is much more complicated than that.
For most modern PC’s there are at least four different types of RAM modules available. Your PC will only be able to use one of these types. The current types of RAM are as follows: SDRAM, RDRAM, DDR, and DDR2. An older module may still be in use on some PC’s more than 7 years old- this is the EDO module. Each of these modules is completely different and is not interchangeable. As you may have also guessed the pricing on each is different as well.
SDRAM is most likely to be used in PC’s that are a 3 to 5 years old. SDRAM modules are of the DIMM configuration (Dual Inline Memory Module) and have 168 pins. SDRAM comes in different speed ratings, PC66 (almost never used any longer), PC100, and PC133. PC133 is backwards compatible with the slower speeds; you can use a PC133 module in a system that requires a PC100 module. However, you cannot use a PC100 module in a system that requires PC133. There are also two types of SDRAM and it is critical that you know what is required of your system. These two types are Low Density and High Density. Essentially, High Density RAM uses memory chips that contain more storage space. High Density modules have less memory chips than their Low Density counterpart. Because of this, High Density SDRAM is about 50% less expensive than their Low Density counterparts. There is a gotcha: many systems cannot use High Density modules. Most Intel systems can only use Low Density modules while some AMD systems are able to see the High Density versions. Plugging a High Density module into a system that requires Low Density will not cause any damage- you just won’t be able to get Windows to work or the PC to boot while the incorrect chip is installed.
RDRAM, also known as RAMBUS and RIMM memory, is difficult- and expensive- to come across. These modules have 184 pins. There are not too many PC’s that use this type RAM. RDRAM was used in some early Pentium 4 systems sold by Gateway and Dell (among others). RDRAM normally has to be installed in pairs- you need two or 4 modules for it to work. RDRAM was touted as being faster than DDR RAM, but never took off. It was also very cost prohibitive when compared to DDR.
DDR RAM is, by far, the most common memory now in use. DDR modules also have 184 pins in a DIMM configuration. All new PC’s we sell use DDR modules. Because of its popularity DDR is also the least expensive RAM you can buy (currently speaking). Like SDRAM, DDR comes in different speeds. These speeds are PC266, PC333, PC400, and for the most extreme performance machines PC466 and PC500. Like SDRAM you can use a higher speed DDR module in a system that requires a slower speed. Also, if you plug a DDR266 module in to a PC that specifies a DDR400 module you will still be able to use that system- just at a slower speed. The system will see this slower module and slow down the memory bus to this slower speed. You also avoid the High Density/Low Density dilemma- there are no High Density or Low Density DDR modules. Almost every PC now on the market uses DDR ram- but this is beginning to change.
DDR2 RAM is beginning to take the place of DDR modules on some new systems. As its name suggests, this module is faster than its DDR brethren. DDR2 modules are DIMM’s which have 240 pins and come in the speeds of DDR2-400, DDR2-533, and DDR2-667. DDR2 is slightly more expensive than DDR, but that is also beginning to change. You can think of DDR2 as being the evolutionary replacement to DDR but DDR2 modules are not interchangeable with DDR. I predict in the next year or two almost all new PC’s will be sold with DDR2 modules.
There are also different modules used in laptops- most of these are either SDRAM or DDR modules called SODIMM’s (Small Outline Dual Inline Memory Module). You guessed right, you must use the correct RAM type even in a laptop.
For an excellent guide on memory and different memory technologies please visit Kingston Technology’s Ultimate Memory guide at http://www.kingston.com/tools/umg/default.asp
Where does this leave the user wanting to upgrade the RAM in their PC or laptop? You have a few options. You can contact the manufacturer of your PC and ask them what you need. You can open the case of your PC and examine the RAM you currently have installed- some modules list their type on a small, white label. Be VERY careful if you attempt to open your PC, you can cause severe damage if you do not know what you are doing and inadvertently touch something you shouldn’t be touching. Also, you must treat RAM modules with care. These modules are extremely sensitive to static electricity. Just carrying the module in your hand a few feet to your PC can destroy it if you are not using proper static disbursing equipment.
Or you can bring your PC to a computer professional, such as the technicians at Pathfinder Networks, and they will steer you in the right direction and get you up to speed in no time!
About the Author:
Parrish Reinoehl is President of Pathfinder Networks; a Niles based technology consulting firm specializing in providing affordable computer services to small businesses and home users including networks, PC support, sales, and service. Pathfinder Networks can be reached at 269-684-7696 or via email at parrish@pathfindernetworks.us
Pathfinder Networks website is http://www.PathfinderNetworks.us
Visit our retail location at 1920 S. 11th St., Niles, MI (in Belle Plaza).
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