The problem is the low end 940m. It's VRAM is relatively small at only 2GB and its performance is lower than the lowest end 1050(not the Ti). In a nutshell your GFX card appears to be the weakest link. It's happiest at 1366x768 with lower GFX settings(in-game).
On a side note - Specifics help a lot when you ask questions about anything. This includes computers. The 6th generation Skylake i5 description is lacking in definition. There are more than 1 6th generation i5. It's like asking an autoparts store which alternator they need for a 2010 Chevy. A Chevy? A Chevy Tahoe?
https://www.piriform.com/speccy is a program that tells the user much about their PC. It can help in the future if you should need some help.
In short, I can't comment on the i5's issues but it's not a dual core so that pushes the blame over to the more obvious suspect.