A Radeon HD 7990 for $145? Wow, all I can say is... What a steal. AS for performance, You would see a significant performance increase. I wouldn't say massive but it will definitely be noticeable. As for cons of the card, I would say that it is extremely power consuming (recommended Power Supply Wattage is 750W.) And I don't know if it would matter to you, but it also requires 2 8-pin connectors.