I wouldn't necessarily consider the 460 to be a bottleneck, I'm assuming this is a Skylake i7 considering the fact that you are buying it now. The Skylake i7 will handle any graphics card just fine, so technically, in most cases, the gpu will be the "bottleneck" of your system, even if you're running a single 1080.
However, if you intend to run high end games on highest settings and get 60fps in 1080p(correct me if you want something different here), then the 460 will not be the right card. If you are okay with dumbing down the graphics a little to get decent framerates, then yeah, the 460 would be a good card.
If you have the money, go for an rx 480 or a gtx 1060 over the 460, you'll be much happier with the results.