The short answer to how much memory you need – regardless of computer manufacturer – Mac or PC, is you need as much memory as possible
There’s a good chance that you need to upgrade the laptop you’re using to read this with, as out of the box and direct from the factory, unless you bought a CTO (configured to order) PC that you chose to fill your laptop with, there’s a good chance the RAM you have installed is just enough to RUN the operating systems and not much else.
Apple Mac OS Snow Leopards Minimum RAM Requirements are 1GB, and 5GB of hard drive space, yet that is JUST for the operating system to RUN, and not much else, including the iApps such as iTunes, iPhoto and the like. And if you need to run Aperture or any processor intensive application that uses memory then the minimum recommended ram of 1GB for MacOS
On the Windows side of things, you’ll need even more memory. 1GB will do you for running 32 bit Windows 7, but if you need 64 bit Microsoft Windows for your laptop OS then 2GB is the minimum RAM you should have installed
As you can see, 1GB or even 2GB really isn’t a whole lot of RAM if you want to do anything with your computer than start it up. (try installing windows 7 or even Mac OS on a 1GB laptop and you’ll see what I mean)
In 2011, the minimum RAM I would recommend for every day computing is 4GB. 8GB is better if your notebook computer can accomodate the larger memory size, but if you’re looking to buy and upgrade a notebook computer in 2011 you’re best to max out your laptop to 8GB if you can.
Best RAM Prices for Laptops.
There’s a very good chance your laptop takes DDR3 1333Mhz memory upgrades and below is a table of the best notebook prices I have found on sale from memory stores you can trust that are much much cheaper than if you bought the memory from the PC manufacturers directly.