So my macbook has required a lot of comfort recently. Comfort in the way of ice packs and a small whispering “shhh, it’ll be ok, I’m sorry, I won’t make you play flash while I also try and edit audio”. I upgraded to Lion a little while ago, because I realised I had a free license, and I really wanted to use my recipe app on my macbook as well as mobile devices. After mostly altering all the settings and installing ‘fixes’ to make it act *exactly* like Snow Leopard (except for the scrolling, I like that) all was well… for a while. Either it was the OS upgrade, or generally old age (this laptop is a mid 2009 unibody 13″, so 3 years, nearly, which by-the-by is roughly 2 years longer than any other laptop I had) but it was beginning, for the first time, to struggle a little. I did a lot of Terminal>Purge, and killing operations (flash mostly) in Activity Monitor (Mac for Task Manager), but it was just starting to get a little annoying, mostly it was the overheating, the fan would whirr away like anything no matter what I did. So after balking at upgrade costs via Apple, I decided to DIY it. And why am I sharing it here? 1) because it’s SO EASY 2) because it will save you SO MUCH MONEY 3) because it will make the machine RUN LIKE IT’S MADE OF SILK. This is aimed at all you artists, companies and creatives out there who really can’t afford to do anything else. I promise you, don’t be scared, this will be fine. There are ace instructions for all the different types of machines on the Apple site, but I wanted to put photos up, so you see it really is just like that. Obviously it’s done at your own risk, but really the worst that’s likely to happen is that you lose a screw. TOP TIP have a ball of blu tac and stick them in that. Now, let’s go.
First off, RAM (memory, it’s what does all the immediate thinking on your computer, and talks to everything else, sort of. Go read Wikipedia) should be installed in this case in 2 x equal size. e.g. 2 x 4GB modules in this case. This cost £39.99 on Amazon, Crucial is a reliable manufacturer, this link will work if you have the same model mac as me, a bit of googling (‘ram upgrade kit <insert year, size> macbook pro’) should sort you. Once you have that you’ll need a very small crosshead screwdriver that is quite shallow. Use blu tac to take an imprint of it to your local Maplin if you’re unsure. Anyway, this is what the kit arrives like:
Step one: back up, then turn the laptop off, unplug, and turn it over so it’s base-up. Use your screwdriver… to unscrew the screws on the back of the laptop case, there should be 3 long screws back right, and the rest are tiny and short. Watch they don’t escape.
The base should lift off really easily, with a little prising, no tools needed, just nails. Look, insides! 
BEFORE YOU TOUCH ANYTHING. Discharge yourself (in case of static electricity) by touching a metal bit of the inside of the case. I’ve never known if this is an actual thing, but I’ve always done it, because they tell you to. You could also use one of those discharge wristband things, if you’re the kind of person who has one…
Step two: Middle right of the set up you’ll see the RAM, it’s big, green and black and hard to miss. First you need to take out the old stuff, there are two clips holding it in place either side, simultaneously (only one half of this direction pictured as I needed my other hand to take the photo) push these clips apart, and the first little board should pop up.
Grasp the memory by the little notches and gentle pull out, repeat the above and below with the second bit.
Step three: now it’s time to put in the new stuff! Important thing: don’t touch the gold bits, hold it by the notches, always. To fit the two new bits of RAM, just push the board, black bit and gold bit facing up, into the bottom of the two slots, making sure the notch in the gold bits lines up. Push it in firmly until it locks. This will make physical sense to you after having taken the old stuff out.
Repeat with the second bit:
Then put the base back on, screw back in all the screws (three long ones top middle – right). Turn the macbook on. Hold your breath, and all being well. DOUBLE THE RAM
(when you find out that doesn’t necessarily fix your fan issues, do an SMC reset… and reassure yourself that you did actually need the upgrade, anyway)
I undertook the exact same procedure on mine a couple of weeks back, decided that 3d animation requires more than a 3 year old mac book pro.
I have been eyeing up that new fancy retina machine for a little while now, But its screwless so if you ever want to put more ram in you have to send it to apple, or make a date with the ‘genius’ bar. Tut Tut apple.