Benchmarks: Overwatch, Mirror's Edge Catalyst, Mafia III
The GTX 780 also performs fine in Overwatch at 1080p with an average of 149fps, placing it roughly on par with the R9 390 (the GTX 780 was just 4% slower).
The GTX 780 remains strong at 1440p as it turns in a rather strong minimum frame rate. When looking at the average frame rate it was able to match the RX 470 while it wasn't much slower than the R9 390.
Testing with Mirror's Edge Catalyst shows fairly consistent performance across the mid-range GPUs along with the titans of yesteryear such as the GTX 780 and R9 390. Here the GTX 780 and R9 390 are quite evenly matched, though the Radeon did offer slightly better minimum frame rate performance.
Jumping to 1440p, the GTX 780 slips away a little and is now roughly on par with the RX 470. This isn't a bad result for the 780 and frankly this is where I would expect to see it in relation to the R9 390.
Mafia III doesn't play well with current generation hardware so I wasn't expecting the GTX 780 to deliver much. That said, it was able to match the RX 470, albeit with an average of just 38fps.
Much the same was seen at 1440p. Here the GTX 780 did match the R9 390, though both averaged under 30 fps so, not really a noteworthy result.