With a GT 730 you will need to lower your settings in games significantly and possibly even have to lower your resolution. As for the GTX 980TI bottleneck, heres what somone said on Toms Hardware.
Yes it will run all those games on Ultra 60+ fps on 1080p.The I5 6400 won't bottleneck the 980ti!
Hers the post:
http://www.tomshardware.com/answers/id-2819101/6400-bottleneck-gtx-980.html