The more memory you have on your laptop, the better. Your OS is bound to perform better and the speed will also be higher. So how do you know exactly how much laptop memory you need? And is there a limit to how much you can possibly have? Well, yes there is a limit. The most advanced laptops support around 3GB. Though the manufacturer may have quoted up to 4GB, only 3GB is used. The first thing you need to know is how much memory each of your application, including software requires. Add up the total so that you have a minimum amount to work with. You need to buy memory that is higher than the required amount. To be on the safe side, it is best to have the highest amount recommended for your type of laptop. 2GB is what is mostly recommended.
Note that different Operating Systems use different amounts of memory. With 2GB, it does not matter what operating system you use. There will be sufficient RAM. Before buying less than 1GB, confirm whether your laptop uses integrated graphics because these tend to use up a lot of RAM. If that is the case, then you will need a higher amount of memory.