TitanX and 980 Ti are not on a par
Once you start overclocking both the 980 Ti runs out of gas first as they are already carrying a heavy factory overclock.
The problem with review sites comparing factory overclocked 980 Ti's to Factory stock reference TitanXs is just that. Whats more the TXs were reviewed when they first came out, since then the drivers have improved a lot.
As jayz2cents showed when he compared an overclocked Kingpin 980 ti to a his slowest TitanX also overclocked using the same setup and modern drivers, the TX came out on top. Remember the Kingpin 980 Ti is the fastest one on the market and also has the advantage of being the only one that comes with Samsung Memory.
Then there is the matter of the 12gb frame buffer on the TitanX which means it can run every game on the market maxed out @2160p when SLI is used.
The 980 Ti is a very good card but it still uses a cut down GM200 chip and only half the memory the TX does.
Also in the news, my GTX 980 Ti arrives today.