The mx series cards are crap for enthusiasts.
But looking at your computer, I'm sure it will give you the performance boost you're looking for.
However, it will NOT serve you in the long run.
Thus, the next time you're upgrading your whole computer, I'd go for a clone computer (assuming you have basic knowlege of computers and stuff).
The upgradebility of a clone computer is far superior to a brand computer. Though, clones may arise some compatibility problems.
My apologies if my text is somewhat incoherent, I'm a bit drunk. It's the first of may