rendering issue getting slow render

hi

I have HP z800 workstation with quadro 3800, 2 Xeon 2.96GHz 8cores 16 thread processor, 256 GB SSD start up disk, 12GB ram of ram. but the system is very very slow while rendering a comp, i already have i7 2600k 8gb ram with nvidia gtx210 1gb graphic card! while i render with same work file in i7 configuration it take 19mins to render that comp, while i render same comp in hpz800 it takes 14mins to complete, i am shocked seeing this different. pls help me to make it fast.