Having a quality power supply for your gaming rig is essential which is usually overlooked by many Custom PC Builds. There are some important features in a good PSU for gaming that must be taken into account such as; continues power output, number of +12V rails and output Amp, efficiency and protection, cooling, noise and cable management.
The very first thing you need to consider before buying a PSU is the amount of output power required which is shown by Watt (W). Usually for a single Graphics card a 550W power supply is sufficient but many brands on the market use misleading power output labels and falsely advertise their peak power output as continues power output, so make sure you go with a well-known brand.
+12V rails and Amp:
When you play intensive games under full load the CPU and Graphics cards are the two main components that draw power from your PSU. Power supplies provide +3.3V, +5V, and +12V to the PC. Because most modern CPU and Video cards need higher electric current (Amp) under full load, a good power supply will have two or more +12V rails to individually provide power for CPU and graphics card.
Efficiency and Protection:
Efficiency basically refers to the ratio of the input to output power and expressed in % and the remaining percentage indicates the power wasted as a heat. Higher efficiency means more cost savings on electricity bills. The PSU's are classified by their power efficiency into six main categories including, Basic, Bronze, Silver, Gold, Platinum and Titanium. The power efficiency is shown by measuring power drawn by the PSU from the wall under 20, 50 and 100% load.
Higher rated PSUs are typically built to a higher standard, thus will generally have sustainable voltage levels, quieter fans, have a quality capacitors that will last longer and in the long run will save you some $$. Always go for power supplies with minimum 80+ Bronze rating. In addition to efficiency, a high-quality power supply can protect your internal component against voltage spike and provide better voltage regulation to your system.
Cooling, Noise and Cable Management:
A good powers supply usually incorporates a fan with higher grade ball-bearing that is durable and operates at higher speeds without making excessive noise. If you want to keep your computer case nice and tidy, always pick a semi- or full-modular power supply to have some or all of the power cables detachable. This will give you the option to connect the power cables as required by your components and get rid of the unwanted cables inside the computer case.