Upgrading RAM

Here is a link to the Apple definition for your question:
http://docs.info.apple.com/article.html?artnum=107918

From Apple
Inactive memory
This information is no longer being used and has been cached to disk, but it will remain in RAM until another application needs the space. Leaving this information in RAM is to your advantage if you (or a client of your computer) come back to it later.

Essentially another program can take this RAM if need be, but it is retained in memory so that if that application launches again, it can quickly use it.

I think upgrading would be beneficial for you. RAM has really dropped in price. There are many threads on here with links to well priced memory.

 

That depends on how many applications you have running at once. Personally, I would think you would see a bump in speed just going up to 1GB from 512MB, but that is my opinion. You can get for a great price for 2GB too which would be good if you want to run Parallels or VMWare sometime in the future.

 

There are experts on here better to ask than me. It looks like it would work fine, but I have not had any experiece with the brand or store. I read somewhere else on here that people have had good experiences with that online store though.