It depends on the games you're playing, . The i5 2500 is definitely bottlenecking the video card in lots of games but the Ryzen 1400 is still not enough for a 1070 if you're playing at 1080p resolutions in CPU intensive games like Battlefield 1/V.
Example: I have a 1070, I have a 6700k at stock speeds, in Battlefield 1 they are very well paired as the processor is very loaded most of the time but just gets over 95% usage in certain moments and the GPU is still working at 100% so there's no bottleneck at all. But the Ryzen 1400 is noticeably slower than the 6700k, even overclocked against the i7 at stock speeds. Battlefield 1 is around 100FPS at 1080p/ultra with this configuration.
Nevertheless I can easily get 240FPS for my 240Hz...