Theoretically it's possible to stream almost all 1080p videos without buffering if you have all that speed at your disposal. However, the internet is not perfect and periodic slowdowns often occur. This means that your 5 Mbps connection cannot transfer data at maximum speed all the time. Therefore even though it's mathematically possible to stream without buffering, things are different in the real world. On a good day you won't see any buffering on a FHD video but during busy hours, you'll see slight but acceptable buffering once in a while. If you want to stream 1080p with no buffering almost 99% of the time, you need additional headroom for the occasional slowdowns - that means a faster connection. This is simply because when, for instance, a 10Mbps connection slows down, it won't get to the level of a slow 5Mbps connection. Therefore you have a little more headroom to ward off potential buffering. You could get a dedicated 5Mbps connection which assures you of almost all the bandwidth all the time. From what I understand, most fiber optic connections in Kenya are shared hence you're safer going for at least 10Mbps. Dedicated lines are naturally more costly than shared ones.