X4 860K will bottleneck a R9 280?

Solution
No. It should be fine. Even better if you overclock it but even at stock speeds it should not be an issue as a bottleneck. There may be CPU intensive games that the 860k doesn't perform as well as some other processors on but as far as being a bottleneck to the R9 280, it will not be, at all.
No. It should be fine. Even better if you overclock it but even at stock speeds it should not be an issue as a bottleneck. There may be CPU intensive games that the 860k doesn't perform as well as some other processors on but as far as being a bottleneck to the R9 280, it will not be, at all.
 
Solution
GTA 5 is somewhat CPU intensive, especially in certain situations, but depending on your settings and resolution you should be ok. And I think you meant 4.4Ghz. An Intel chip would offer better performance in CPU intensive situations, even lower clocked chips due to Intel processors having a higher IPC (Instructions per cycle), but as far as being a bottleneck, it won't. What is your budget for the build and what exactly do you need?
 
Yeah, those Youtube gaming videos are often modified or outright faked. I just linked to it to show you that the game is playable with that hardware, not that you're going to be capable of ultra settings, because you're not, unless you have a very low resolution and probably not even then. BUT, you should be able to configure a very playable experience if you make a few tweaks and adjust the settings appropriately as well as have a good clean driver installation using the latest stable drivers.