Budget

If your budget is less than $1,000; I would suggest you buy a PC from a brand manufacturer. PC makers have the economy-of-scale to buy commonly used PC components in bulk at a much cheaper price than you can buy from a retail shop. In today's standards, a reasonably priced PC can be used for most applications and games without delays and performance degradation. However, requiring video manipulation such as YouTube editing, playing modern games, or even playing Virtual-Reality (VR) games, you may opt-in to build your own highly scalable PC. My personal demarcation for building a new PC will be a $1,000 price break. If you spend more than $2,000; your dollar per performance return will start to diminish.

Components

Let's assume that you chose to spend more than $1,000 and decided to build your own PC. You'll have to decide on the individual components that will make up a PC, and they must be all compatible. Also, you'll have to balance the performance of individual components so that your CPU is powerful enough to support the $300 GPU that you intend to purchase. Besides the components, you'll also need a toolkit to assemble the PC without breaking the components. In a nutshell, you'll need the following components to build a PC.

• CPU & Heat Sink - CPU is the brain of the computer and it is measured against the model & generation, number of cores and clock speed. For example, a performance benchmark between Intel's 2nd generation i7 CPU will be different from than 6th generation i7 CPU. The number of cores (Dual, Quad, Octa, and etc.) allows simultaneous processing of instructions, and having more core will perform better. The clock speed also plays a significant role in CPU performance as instructions are processed as fast as the clock speed (sliced seconds).
• Motherboard - The motherboard must be compatible with the CPU you've chosen. The high-end motherboard allows you to overclock the CPU if you choose to overclock. The motherboard has RAM slots, USB, and default Video ports, so picking out a motherboard with an adequate number of memory slots (for maximum RAM support), USB ports and video interface is very important.
• Memory (RAM) - Random Access Memory is the memory used by the CPU. Having more RAM will perform better because it will not require swapping of data from fast RAM to slow HDD when not enough memory is present in a system. Today's standard begins with about 4GB, and having 8GB will be sufficient for an average user's performance. If you require multi-processing and play memory-intensive games, you may increase the RAM to 16GB or even 32GB.
• GPU - Graphics Processing Card is the one that will impact your video performance. If you see a delay in video performance, your GPU will improve the graphics performance. Much like the CPU, GPU has the clock speed and also offer Video RAM. For 1080p video, you can use a GPU with only 2GB but 4GB will offer you high-definition textures. And, having more than 6GB of VRAM will offer 4K video with high-definition textures.
• Storage (HDD, SSD or M.2) - You'll need an external storage space to store OS, applications, and data. The traditional HDD is the slowest storage, while SSD (Solid State Drive) and M.2 perform faster.
• Power Supply Unit - Power Supply is the unit that powers your PC. Depending on the accessories and components used, you'll need a power supply that is capable of powering all of the components enclosed. The traditional power supply has 250W power, but the higher-capacity power supplies can have 500W, 750W, and even 1,000W power.
• PC Case - The PC enclosure is more of a design than anything else. The modern PC case has a transparent case with varying lights to make it look cool. Also, some high-end cases offer cooling features.

Operating System