What Are the Four Types of PC Power Supplies?

Every computer needs a reliable power source. The PC power supply keeps every component alive with its reliable, constant DC power, derived from AC power in our homes. Each component requires a different voltage to operate in a computer, so a computer power supply has 12V, 5V, and 3.3V power rails. Modern power supplies are not only a source of power for computers but also protect against power fluctuations. This is accomplished through international safety certifications such as ISO 9001.

Power supplies are categorized into 4 types, each with distinct features: ATX, SFX, TFX, and Flex ATX. PC builders need to select the correct form factor for their computer because an incorrect power supply not only provides an unreliable power source but also causes poor airflow and insufficient connectors, making it difficult to connect each component correctly.

1. ATX Power Supplies

1.1. Features and Specifications

If we talk about ATX PPSUs, they are the most widely used power supplies for modern CPUs, with dimensions of approximately. 150*86*230mm. They are ideal for providing good airflow in CPUs that generate high heat. They are primarily used in full- and mid-tower cases. Most people using high-end graphics cards, such as NVIDIA RTX 40 series, require 12HPWR connectors (12+4 pin), which are available in ATX (ATX 3.1 and PCIe 5.0 standards), making them ideal for gamers. Modern computers have high power consumption, which ATX-type PSUs can readily supply, as they are designed to deliver up to 1200W. Since your computer is expensive, it is equipped with Active power factor correction and other necessary protections (OCP, OVP, SCP, OTP, and UVP) to prevent damage from power spikes.

1.2. Ideal Use Cases

Modern gaming rigs, professional workstations, and content-creation PCs have multiple drives and multiple GPUs with advanced cooling systems that require more power, which ATX can provide when used in either full tower or mid tower casings if designed to operate at 60-70% load(750W CPU provided with 1000W PSU), ensuring good efficiency.

1.3. Supplier Example

If you are looking for the most advanced ATX PSU, ESGAMING EFMG1200W is the one for your PC. It's been certified at 80+ Gold and has 90% efficiency at peak loads. Some other specifications include a 12V single-rail power supply, smart thermal control, and an FDB fan. Protections provided are OCP, OVP, OPP, SCP, and OTP.

2. SFX Power Supplies

2.1. Compact Design

The size of SFX(Small Form Factor eXtended) is much smaller than ATX. If you are considering comparing sizes, SFX is 25 × 63.5 × 100 mm, which is 60% the size of ATX. Still, in terms of performance, there is no compromise, and it can provide you with equally reliable power as ATX. Since SFX is smaller, they are ideal for use in mini-ITX and micro-ATX cases. SFX also comes with 12 V, 5 V, and 3.3 V rails and a protection system that includes Active Power Factor Correction (APFC) and multiple safety protections, including OCP, OVP, SCP, and OTP.

2.2. Performance and Trends

SFX can provide up to 1000W of power, so many mid-range computers, including gaming and graphics workstations, use SFX as a reliable power source. Similar to ATX, SFX also offers an 80+ Platinum rating and 90% efficiency. To improve performance and address cooling issues, SFX is designed as a modular system. To provide the latest technology, SFX supports PCIe 5.0 and 12VHPWR connectors.

2.3. Market Relevance

Many designers use small-form-factor PCs with multi-core CPUs, which require minimal space. For such a PC, SFX is ideal due to its unmatched power density and airflow efficiency. With its compact design, SFX stands out in the market as a small, robust solution for small-form-factor PC designs.

3. TFX Power Supplies

3.1. Slim Profile

As the name suggests, it has a slim profile, with chassis dimensions of 85 × 65 × 175 mm. It has a narrow, long chassis, which is used when the CPU has limited internal space. TFX is equipped with an 80mm fan that directs airflow along its length. Since TFX is slim, it prioritizes efficiency over raw wattage. Most TFX-powered computers are horizontal, as it's easy to manage airflow with the TFX PSU.

3.2. Efficiency and Power

TFX comes with an 80-plus bronze certification, providing 80-85% efficiency and an added benefit of low heat production and low energy waste. TFX power solution offers a power output range of 300-600W. Mostly used for low-power GPUs, like all other PPSUs, they also have standard 12 V, 5 V, and 3.3 V rails, making them compatible with most computer components. An extra feature that has been most important to discuss here is the 21ms holdup time. This feature allows TFX to maintain stable power during short power fluctuations. TFX power supply also has special features like Active Power Factor Correction (APFC), smart fan control, and low-standby power consumption (under 0.3 W)

300-600W, 80+ Bronze

3.3. Applications

TFX units are slim and low-power, making them useful for home theater computers and business desktops where a mighty PSU is not required. Only a PSU with a reliable output, low noise, and consistent performance is important

4. Flex ATX (Advanced Technology eXtended)Power Supplies

4.1. Versatile Form Factor

ATX power solutions are ultra-compact, with dimensions of approximately 81.5 mm wide × 40.5 mm high × 150 mm deep. They are suited for computers with chassis that do not accommodate ATX, SFX, or even TFX units. Some distinct features of ATX include a compact internal layout, efficient cooling paths, and a non-modular design. All these features enable companies to reduce costs while maintaining reliability.y Flex ATX are manufactured with high-density circuit boards, limited spacing between components, and good heat-resistant material

4.2. Specialized Use

Flex ATX is small and delivers up to 500W of power, making it suitable only for industrial PCs, workstations, small servers, and embedded computing platforms. In all these systems, constant, reliable power output and space are equally important. ATX are used in industrial units that require 24/7 continuous, reliable operation with stable voltage and sufficient holdup time under AC voltage disturbances. In industries, ATX is used in a redundant setup where one PSU fails, then the backup PSU will take charge

4.3. Industry Standards

ATX units are manufactured with 80 Plus Bronze certification, with an efficiency of 82-85%. With this efficiency, we will achieve reduced heat output and improved reliability. Flex ATX is also designed with UL, CE, and CB certifications and qualification tests related to thermal rating and vibration

5. Choosing a Reliable PC Power Supply Supplier

Selecting a reliable PSU manufacturer is very important. A good manufacturer must be manufacturing PSUs under controlled conditions in accordance with international standards such as ISO 9001, and the end product must have 80+ certifications. ESGAMING, one of the best suppliers in the market, claims to have a modular PSU with 700-1200W that can be used in next-generation computers. Silverstone and FSP are also considered essential manufacturers for PSU, offering ISO9001+OEM/ODM services. If the supplier provides all these specifications, you can consider buying a PSU from them

6. Conclusion

In building a PC, the PC power supply is a key component, like the heart in the human body. We have discussed all 4 PSU types. I hope you can now understand the key features of each type. ATX has a high-wattage rating, SFX has a compact chassis with high power, TFX is very slim, and Flex ATX is ultra-small. After all our discussions, you can select the PSU that best suits your requirements.

If you are looking for a wide range of PSUs spanning a power range of 700-1200W and featuring 80+ Gold efficiency, then consider ESGAMING. The offer OEM/ODM production, which makes them experts in their hardware. Visit their website to explore all the options.