Renegade 13 said:
I'm looking to upgrade from 1GB to 2GB. The question is, do I need to buy the extra Gig from the same manufacturer or is RAM compatible across manufacturers? As it is, I could end up with 2x512 from one manufacturer, and 2x512 from another...would this work fine?
As far as I know, RAM is RAM is RAM. It shouldn't matter who made each chip, unless it is some shoddy Chinese junk manufacturer... Just make sure to get them all the same clock frequency, since the motherboard will run all RAM at the frequency of the lowest chip.
Another separate yet related question; is there any way to determine the manufacturer of a particular component without physically cracking open the case and checking the labels? I have the idea there is a way and spent a while poking around the various device managers, but couldn't seem to find it. If anyone knows, please help! 
Device manager is not always helpful, especially if you have components using generic drivers. Try Belarc Advisor, which I believe reads all the identification bits for each piece of hardware, as well as driver info:
http://www.belarc.com/free_download.html