Can I make a suggestion?
Post your computer's specs for us, so we can suggest the best card FOR YOUR SYSTEM.
Specifically, make/model of your motherboard. Ideally, can you give us a link to the homepage with the specs?
But also,
1. what is your CPU
2. how much ram do you have, and what speed is it?
3. what make/model is your power supply and how many watts is it rated at? (your current psu may not be enough to power a newer card)
Let's start there.