You don't need to match the monitors refresh rate though. A single 980 ti will give you solid frame rates at 1440p.
As already stated - not true
Got a single 980ti running a Rog Swift 1440p at full settings on latest games without issue
I can't recommend this enough. I'm gaming at 1440p on a 60hz panel and there is plenty of grunt left if I was to upgrade to a quicker unit. The games I play with v-sync see no frame drops whatsoever...so yeah, single 980Ti for a 1440p panel

I was an IT monkey in The City. Then I inherited daddies money. Now I deal in commodities and invest in Private Equity type business turn-arounds.
Will go for 2 Ti980's. Calling OCuK later to see if they will build my spec
Have you settled on a spec then?