I recently decided to upgrade my computer the most that I can to extend its usefulness. I found a good deal on Hynix 4GB (4x 1GB) HYMP512F72CP8D3-Y5 AC-C PC2-5300 DDR2-667MHz ECC Memory but it didn't fit. I thought all of the specs checked out but apparently I missed something. What is the fastest/most ram that I can use and how can I know if it will fit or not before I buy it?
You're better off investing in an SSD than faster RAM. The difference in performance from faster RAM will be barely noticeable, if at all.
With how old my system is, I can get 4GB of ram for less then $10 from ebay and I already have two hard drives. There is a lot that I will do when I have the money to invest into the system that I want but until then I'm looking for ways to extend the life of the system I have for as little money as possible.
For $10, it's hard to lose, but I can't see it making much difference unless you're doing heavy work like database development.