If you want one of the easiest and cheapest ways to improve your MacBook’s performance, you don’t have to upgrade your Mac. If you’re hurting for a computer that runs as smooth as silk, consider upgrading just the RAM instead.

If you’re running OS X Lion, you’ll want to upgrade your RAM to at least 4 GB, but we recommend 8 GB, instead. The result? A way faster computer without the plunge into your pocket for a whole new one.

If you have the instruction booklet that comes with your Mac, chances are you have some instructions from Apple for trading out your RAM.

It might seem a little worrisome to get started — after all, you might be thinking that, if you blow it, you’ll blow your computer. Don’t worry, this isn’t the case. Changing the RAM is actually really easy, and all you need is a single tool and a bit of time.

The first step is to make sure that all of the requirements and specs of the RAM you’ll be getting is the same that your current machine will accept. If you don’t, it might not work properly. You also want to make sure that you take the amount that it will hold. Some 2007 models, for example, can only hold 4 to 6GB, whereas newer ones can top 8GB.

If your Mac has two RAM slots, you want to make sure that it has the same amount of RAM per slot (IE 3GB and 3GB if you have 6GB in total). When you split up the RAM, it won’t work as efficiently. Furthemore, look to get all of the RAM from the same manufacturer, as well, for the best performance.

After you have the RAM, gram yourself a Phillips screwdriver (#00), and a guide on how to do it, such as Apple’s.

It’s important to note that some Macs, such as the Air, are impossible to upgrade, but most other models are pretty easy.

If you have a pre-unibody MacBook Pro, it is super easy to do. The first step is to remove the battery, then use the screwdriver to remove the four screws that are on the RAM shield and the shield itself. It takes about 4 minutes to slide the new one in place, screw them in, and then replace the battery. You’ll be good to go.

If you have a pre-unibody MacBook, this is easy, as well. Just remove the battery then loosen the screws on the retaining bracket. Remove that, and the RAM is right there (so is the hard drive, if you ever need to get into that). Apple also puts some release levers there for it to easily pop out by pressing it down.

Unfortunately for owners of unibody MacBooks, the process isn’t quite as cut and dry. For those who have a polycarbonate unibody, it is a little more complex, but still pretty easy. You’ll have to remove 8 screws to start off, and remove the backing. The RAM is there, but it is in between the logic board and the hard drive. It might be a little lodged in, so you want to be sure that you’re careful. But, alas, you’ll get it out, swap the new one back in, and you’re set. The same here goes for the unibody MacBook Pro. This can all seem intimating because users will realize their whole bottom half of their laptop is exposed. But don’t worry – just get in, get out, and you’re fine. Then close it all back up.

When the MacBook is all closed back up, open it up and start it back up. You can easily verify that the MacBook recognizes the newly installed RAM by clicking on the Apple menu. Then choose “About This Mac”. Your new RAM should be showing and you’ll soon realize how much better it really is.

And you didn’t even have to buy a new MacBook.

(Oh, and once it is installed? Get Lion. You’ll be happy you did).