You've probably landed on this page because you either want to get up to casinobrango with what DDR laptop memory is or you're bang in the middle of trying to upgrade your laptop but stuck what to do. Well you know what? You've probably landed on a page that can help!
A good place to start is an introduction to DDR laptop memory...
Types of DDR laptop memory
DDR stands for Double Data Rate and is an enhanced (faster) form of SDRAM (Synchronous Dynamic Random Access Memory). Virtually all laptops sold today as well as those sold since circa 2002 use a given (older or newer) version of DDR laptop memory. Put it in plain English DDR memory is faster than standard SDRAM because it can transfer data on both the falling and rising edge of each clock cycle and hence the 'double' in its name. There's absolutely no reason you should remember this but just note that if you ever see DDR SDRAM mentioned anywhere, be sure to appreciate this is the exact same thing as plain vanilla DDR.
So moving on, what types of laptop memory do we have?
DDR laptop memory, otherwise known as DDR1 (though this isn't an official name instead referred to as just DDR) or DDR SDRAM is the oldest and slowest. It's predominantly available in capacities up to 1GB (per module) and at speeds of up to 400MHz (effective).
DDR2 is an evolution to DDR with some internal enhancements to boost performance and usually available in capacities up to 2GB (per module) and speeds up to 1066MHz (effective).
DDR3 is presently the latest form of laptop DDR memory and is yet a further evolution of DDR2 boosting speed a further notch. It can be found in capacities up to 4GB (per module) and speeds up to 1600MHz (effective).
Notice that we could have said DDR2 SDRAM just as DDR3 SDRAM. For simplicity sake, stick to remembering that there's DDR, DDR2 and DDR3 because quite frankly this is what you'll encounter most! Luckily, the industry seems to prefer the shorthand naming convention.
You may also want to discover more about DDR, DDR2 and DDR3 laptop memory.
How do the above types relate to your laptop? This we'll examine next!
What type of DDR laptop memory do I need?
When upgrading laptop memory you need to identify what type of DDR memory is used thus supported by your laptop. Failing to do this will mean a failed upgrade for a very simple reason - all versions of DDR are incompatible with each other and use a different type of slot connector, which differs in the number of pins (and several other technical aspects).
Speaking of memory slots we need to introduce memory modules. In contrast to desktops your laptop uses a smaller form of memory slot that consumes less space. As a result, the memory modules used in laptops are smaller too. You may or may not have heard the term DIMM (Dual In-line Memory Module) before, especially if you've upgraded your desktop computer (now is a great time to jog your memory!). Laptops use SO-DIMM's - simply append 'Small Outline' to a DIMM. The name isn't very important except what this means in practise, namely you cannot install a DIMM in a SO-DIMM memory slot and vice versa. DIMM's are considerably longer than SO-DIMM's and are not designed for use in laptops. Before going further we should also point out that you may stumble upon SO-DIMM written as SODIMM - this is the exact same thing!
So just to recap, we know the different types of DDR, that various versions of DDR don't mix and also that we can't use any DIMM's lying around the house and/or office (should you have any) in our laptop. Next we need to conclude just what type of DDR memory we need, specifically what will work in our laptop.
A good indicator what type is right for you is your laptop's age. Laptops produced in the years 2001-2003 will be very likely be DDR based. Laptops produced in the years 2004-2007 will be DDR2 and finally, laptop made since 2008 will be DDR3 (though some use DDR2). Armed with this information you'll know whether to buy a DDR SODIMM, DDR2 SODIMM or maybe a DDR3 SODIMM.
A second aspect you need to evaluate is the memory controller within your laptop. A simple method to find this out (and be told what type of DDR is right for us) is to run some diagnostics software on our machine. The truth be told, there are tens and tens of alternative ways to approach this. We recommend downloading and running CPU-Z, it's entirely free - download CPU-Z here. This simple yet helpful application will amongst other aspects tell us what memory our laptop uses therefore supports (remember what we said about not mixing types of DDR?). Click on the 'Memory' tab and also the 'SPD' tab. There you will find the name DDR, DDR2 or DDR3 followed by various odd looking numbers such as the memory frequency and different timings. You will also find the name that corresponds to the sub-type of DDR laptop memory used by your laptop - this will be something along the lines of PC2-5300, PC3200, PC3-8500 etc. Simply piece the two together (i.e. DDR2 PC2-5300, DDR PC2100, DDR3 PC8-8500) and you'll know what to buy and therefore install.
Find out more about DDR, DDR2 and DDR3 SODIMM modules.
We know what memory we need, a logical next step is therefore to decide where to buy it!
Where to reliably buy DDR laptop memory
In this day and age when the Internet overwhelms in options from where to buy laptop memory it's impossible to provide a definitive list of safe online outlets. For this sole reason we won't journey down this route but instead suggest you buy your laptop memory upgrade from names that have been in business for years and are thus reliable. As for the make of memory you may end up buying from any of these stores, do pay note if it comes with a lifetime manufacturer warranty - almost always it will, but should this not be the case then let this make you think twice about clicking the order button!
Check out where to buy DDR laptop memory that's right for your laptop.
How to install DDR laptop memory
The good news is that regardless what type of DDR laptop memory your laptop uses, installation is very much the same for either. The only key difference (except of course for installing each in a compatible memory slot) is that in the case of DDR2 and DDR3 laptops, it's good practise to install memory in pairs (i.e. two modules at a time). Doing so enables the so called dual channel mode on suitable laptops, which triggers a performance boost (enhanced memory throughput). If you have such a laptop then just remember to order two modules instead of one.
Most laptops feature access to the memory bay underneath. For this reason most of you will want to turn your laptop upside down. Needless to say, you should turn it off first! In other cases your memory might be under the keyboard or touchpad (let's guess....Lenovo/IBM Thinkpad perhaps?). In either case getting inside (lifting the memory bay cover or similar) will be easy providing you have the right Philips screwdriver. In some cases you may want to consult your laptop's manual (these almost always tells you where the memory is installed) for clues what screws need unscrewing (usually 2-3). It's important you earth yourself throughout the entire process as electro-static impulses can damage laptop memory. Either buy a cheap anti-static wristband or remember to touch something made of metal such as a table leg regularly. Either method will keep your body discharged and therefore safe for handling laptop memory.
Once inside, simply remove the existing memory module by pulling the latches at either ends in an outwards direction (if you need to free up space) in which case the existing module will pop up. Simply pull it out once loose. If you don't need to free up space and simply want to insert the new module, align the latch on the slot and module correctly and then insert the module at about an angle of 45 degrees. Once the gold plated pins are hidden (inserted) in the memory slot, press down until the DDR laptop memory module clicks into place!
Next, turn on your laptop and your memory should register all and well. If your laptop fails to turn on then one or more memory modules might not be inserted properly, or possibly (rarely) faulty.
You may prefer to follow a step by step laptop memory illustrated installation guide instead.
Conclusion
Upgrading DDR laptop memory can be difficult but needn't be. First and foremost don't overwhelm yourself with knowledge that won't necessarily help you when it comes to buying and installing laptop memory. Of course, there's no stopping you reading up in detail about laptop memory upgrades but just remember there are aspects you may want to know but don't need to know. Save yourself the confusion!