anyone can help me

not bad for a single video card

hi all

I have doubts about the performance of sketchup model and I work with super heavy and it gets very slow with files larger than 80 mb

my pc
intel i7 3770k 4.3 oc
asus pro p8z77
samsung 16gb ddr3 1600
seagate momentus xt 750 GB solid state hybrid
powersuply silverstone 1000w
now my old xfx ati radeon hd 6870 1gb

what I want is super fast sketchup work as office work and renders models as fast as possible, ie the time is very important

my question ... What video card will give me the best results of which are in the market today? I am very interested to know whether the dual gpu or sli will benefit me in sketchup .... the money factor is not a limit,
and want the best.

I am using for rendering lumion 2

if you recommend another processor or other component ....

thanks before hand