The more I read in this thread, the more I tend to think OP is trolling, but then my little angel on the other shoulder gives him benefit of the doubt. But seriously OP, maybe you should start getting into basic info on how a PC works before you start asking literally every basic thing that happens when gaming. The things you ask are so basic, it's literally all over the internet. Google works wonders.
Just some essential points about PC gaming then, that will probably make you a lot wiser.
- Every PC has a bottleneck. A bottleneck is something that shows you have reached a performance (FPS) limit for your system. In your case, this is the GPU in most games you will be playing.
- Your CPU showing 48% - 60% usage, is an indication of a bottleneck on your GPU. The GPU is doing all it can do (99% usage), and the CPU does whatever needs to be done to 'feed' your GPU. Whenever ONE part of your PC has 99-100% usage, that is your bottleneck. It will also mean that the only way to increase performance further, is to make that part faster, or get a better part. In this scenario that is an upgrade to a stronger GPU, like the 1080.
- Performance levels (and in-game FPS) differs per game, per quality settings, but even within one game FPS can fluctuate wildly. You may see 90 fps in outdoors and once you get inside and a lot of lighting effects are added to the image, you will be seeing much lower FPS, even to 30-40 fps or even lower. This depends NOT on the GPU, but on the game in question. Therefore: you can NEVER say that 'this GPU needs to give me 60 fps at all times' because no single GPU will ever accomplish that. Every combination of game+PC and every different part of the game, every different game engine, will show a different performance.
- Because of the above, what you want to do when purchasing a GPU is consider your 'minimum acceptable FPS' and 'minimum acceptable quality setting'. Get that into your head, and buy a GPU that ticks the boxes. Also be realistic about image settings and the actual perceived quality - most 'ultra' settings do almost nothing above the 'high' setting, but they do give you a crapload of performance.
So if a game ducks below 60 fps, tone it down abit. Tweaking like that will also get you a lot of information about how graphics cards behave, it's valuable experience for future purchases.
Last but not least, I'll repeat this again, NEVER buy Nvidia reference cooling. It's shit, and your card is underperforming or louder than it needs to be because of that.