Just looked at my daughters lap top and thought I was getting 512mb as quoted, but went into systems, as looking for something else, and found I only have 504mb, is this just a mistake or do I need to chase it up?
There are various components in a computer that use resources from other items. In this case the graphic 'card' or something similar could well be using the 'lost' MB of memory. Shouldn't worry about it, as it is a normal procedure.
If you want to find what the laptop contains, then download and try SIW click here or/and Belarc click here Both free to download and use and are well recommended.
The chip(s) that generate the images you see on the screen. It needs some private RAM of it's own.
In a desktop computer this may come as a seperate card that has extra RAM on it, along with the grahics.
OR, as in most laptops, it's not seperate but built-in to the main circuit board (motherboard), and uses a part of the system RAM. This arrangement is both less costly, and more compact (more compact is very useful for laptops, of course.