One of my Macs is about 2009 MacPro running Snow Leopard (because I refused in 2011 to abandon my old standby FCP7 in favor of FCPX and still do!) a single nvidia geforce gt 120 and single 1082 23” Cinema Display. Both have DVI terminals. Can I add an additional 1082 for a dual monitor setup? It worked for my old MacBook Pro but I don’t know if I can do it on my desktop. Thanks for any help you can provide.