How much RAM does your PC have? If you run Windows XP, it is probably in the range of 512 MB to 1 GB. Older Windows versions will do the job with less than that, but as soon as you execute demanding applications or more than one application at a time, anything below 512 MB will likely translate into performance bottlenecks.
Of course, the more RAM you have, the better off you are - but how much memory do you really need?
512 MB
There are a few situations where having just 512 MB system memory in your computer can be enough.
* If you run your games at low quality settings (small texture size) because you have an outdated CPU and graphics card, or because you prefer FPS over visual quality.
* If you only use one application at a time.
* If it is your grandmother's computer.
If you are buying a new computer, even if it's a laptop, opt for more than 512 MB - you will never regret it.
1 GB