I hope you speak English, for my Portuguese is horrible. If not, I hope you can read English OK, because I certainly can't write well enough to ensure my information is accurate.
From what I see, you're having performance issues, but you don't say what they are or how many people are accessing. Also, what version, precisely of 8.2 are you on?
In general, performance comes down to two big things, from what I have seen: RAM and I/O.
How many drives do you have, and in what configuration? 8GB RAM might or might not be enough overall, depending on what this server is doing, and 2 processors might or might not be adequate for your usage.
Can you provide a bit more information about your cluster, amount of data, drives and usage patterns?