Built for Gaming, Rendering (CAD, Video etc.), Game development. I built this computer in one go apart from the Graphics Card.
Gaming: I didn't buy the GPU straight - mostly due to the cost. My dream was to have a high end gaming computer. To do this I didn't want to spend little on both the CPU and GPU. I chose Intel i7 4770 - Best decision of my life. Uses little to no power in comparison to is close competitor AMD FX 8 core. The Intel CPU also has integrated Graphics Intel HD 4600, which I can say didn't disappoint playing most games like BF3, BF2, Insurgency, War Thunder, Overwatch, Arma 2 etc. All games could perform with good FPS and very reasonable quality in game (dependent on the game - most with 720p resolution).
Hard Drives: SSD is very quick and doesn't disappoint, with Windows 10 Installed and as most PC gamers have the clients like Steam or Origin. It's recommended to install your Client on the SSD, but create a library for all your games on the normal 1TB Hard drive. This saves space on your SSD and also means your client is processed by the faster of the two hard drives - improving performance.
Cooling: As I knew I was going to be running a high performance system. I knew cooling was going to be a much have. I knew my case came with some already. But I also knew I needed quiet ones, so also bought the Corsair ones as they also had LEDs as I was going for a White and Blue schemed case. The most important aspect of the cooling I considered was having a CPU cooler which was not stock by Intel. I knew the CPU would be doing a majority of the work, and with the cost of the CPU I would prefer it didn't overheat as this would obviously shorten it's life over time.
The CPU cooler I decided on was purely down to customer satisfaction and review online and the companies reputation for excellent cooling and they also haven't disappointed as my CPU hasn't go above 45 degrees ever. I will say, if you are going to use this CPU cooler. Take your time, be patient. the cooling paste which comes with it is essential. but be gentle and don't use loads of the paste on the CPU. It requires a gentle coat and a plastic or card strip to spread the thin layer over the CPU.
Graphics Card: And for the MSI R9 390. Well after only purchasing this recently (after a long time of saving up). I can only say it's incredible! I am still testing all my games out, but as far as I can tell your can play most games on high/ultra at 1920x1080p and has the capacity to run a 4k monitor including those games in 4K (dependent on Game).
For inserting the GPU - I would recommend again, taking your time, be patient. If you force the card into the pins to much or start flexing the card whilst connected to the pins, your at risk of braking both the Card and motherboard which the warranty will not cover and you will lose a lot of money. Do not be put off - if a 18 year old can do it, you can too :)
Any Queries or Questions Please don't hesitate to leave a comment and I'll try get back to you :)
May need more :)