which non apple graphic card in mac pro 3,1 to use with fcp7-fcp x-premiere?

i'm running a mac pro 3,1/10.6.8/with stock gt8800/512 graphics card.

i'm hoping to eek out a bit more life from this mac pro by upgrading the graphics card.

by upgrading to mavericks (or mountain lion), i can access non-apple graphic cards but lose the boot-up screen.

but i'm unsure of which graphic card will fit/work/be effective in my mac pro.

it has been recommend to me the EVGA GeForce GTX 660 2GB Graphic Card:

http://www.newegg.com/Product/Produc...82E16814130826

any thoughts on the above card?

any other cards that might be a better solution?

i welcome any and all thoughts.

thank you in advance.

be well.

rob
smalltalk productions/nyc