Battlefield 4 can be somewhat CPU-bound, even in the single-player mode that we tested here. So we expected to see the 5820K to give the game a boost here. Indeed, with the GTX 980 Ti, performance is about 2% higher, but as with the Crysis 3 results, Battlefield 4 seems to get stuck when using the Radeon R9 290, meaning that extra CPU power just doesn't help.
The results in this game are really, really close, with a split-decision based on the video card in use. It's a game that we'd expect to be essentially GPU-bound, but in fact the Radeon R9 290 performs better when teamed up with the Core i7-5820K, while the GeForce GTX 980 Ti performs worse. Tthat is most definitely hard to explain! We'd guess that the Radeon drivers in this game may impose an additional CPU overhead, thereby responding positively to the presence of extra cores and overcoming the drag resulting from the use of the 5820K-based system.
Far Cry 4
We end with one of 2015's biggest hits, Far Cry 4. Being a relatively-modern game engine, we thought it might like not just extra GPU power but also extra CPU power as well. Alas, it was not to be, as the 5820K-based system again trailed the 4790K-based system, at least when paired with the powerful GTX 980 Ti video card.