Hi,
quote:
Are there any problems with having 2 different amount of RAM? For example, a 256mb and 512mb. Total 768.
For most computers in use today, no. It's a pretty safe bet that includes yours.
With that said many, of the same computers can derive some performance benefit (dual channel mode or at least interleaving) when the memory is installed in even matched pairs, so you should try to do it when you can. If it's not economical to do so, don't worry about it.
quote:
I have 512mb's of RAM, but it says I have 480mb's of RAM? Why is this? Something to do with my graphics card
Correct. Graphics requires RAM. Chipsets with integrated GPU use part of main system memory for it, which takes it away from all other uses.
quote:
if its onboard, its not a card and doesn't have its own ram...
While generally true, there's nothing magic about placing components on a card rather than soldering them to the board. There have been some motherboards that had a full-blown separate graphics chipset and a set amount of video RAM incorporated on the board, but yes -- that's quite rare.