1 PC/XT Power Supply

　　The standard established when IBM first launched the personal PC/XT machine.

　　2AT Power Supply

　　Also a standard proposed by IBM when it introduced the early PC/AT machine, capable of providing 192W power supply at that time.

　　3ATX Power Supply

　　The ATX specification is an industry standard proposed by Intel in 1995. To this day, ATX architecture power supplies have become the mainstream standard in the industry. ATX is an abbreviation for AT Extended, which can be translated as the "AT Extended" standard, and ATX power supplies are designed according to this specification. Household computer power supplies sold on the market generally follow the ATX specification. The standard size is 150x140x86mm.

　　4BTX Power Supply

　　BTX (Balanced Technology eXtended) power supplies are PC power supplies designed according to the BTX standard. It can be understood as a compromise Intel made for the convenience of branded PC manufacturers. BTX power supplies are compatible with ATX technology; their working principles and internal structures are basically the same as ATX, and the output standards comply with the ATX12V 2.0 specification. Power output requirements and interfaces support ATX12V, SFX12V, CFX12V, and LFX12V. Although technically similar to previous power supplies, to meet size requirements, they adopt an irregular shape. They define three specifications: 220W, 240W, and 275W, with the 275W power supply using independent dual +12V outputs. BTX is not a revolutionary power supply standard compared to ATX.

　　5EPS Power Supply

　　EPS power supplies and Uninterruptible Power Supplies (UPS) are completely different concepts. Starting in 2002, with the development of the digital age, the SSI EPS standard emerged to supply power to new workstations and server chassis. The ATX power supply standard ATX2.03 specifies a 20-pin motherboard power connector and a 4-pin CPU power connector. EPS features a 24-pin motherboard power connector and an 8-pin CPU power connector. Therefore, the commonly seen 20+4 pin motherboard power connector and 4+4 pin CPU power connector on ATX power supplies are actually extensions of the ATX power supply, and the correct name should be "ATX/EPS."

　　Popular household motherboard CPU power connectors often have an 8-pin interface, while the 4-pin on ordinary ATX power supplies can fully meet the power consumption (the remaining 4 pins). The appearance of an 8-pin interface on ATX power supplies is because Intel's Xeon series CPUs require 8-pin power supply—current ordinary CPUs consume more than 70W, so dual CPUs in servers exceed 140W. Converted to 12V, this means over 12A current, and the four thin wires of a 4-pin connector are obviously unstable for motherboard power supply and pose safety risks. The same reasoning applies to the ATX 20-pin connector. Considering future development, motherboard manufacturers first introduced 24-pin motherboards for ordinary household boards, and then 8-pin connectors appeared on single-CPU ATX boards, fully compatible with the EPS standard. Such motherboards can use standard ATX power supplies, but for safety, it is best to connect all wires.

　　6WTX Power Supply

　　WTX power supplies (Workstations TX) are workstation power supplies, positioned between servers and household computers, and can be understood as an enhanced version of ATX power supplies. This standard was proposed due to the emergence of the Pentium III Xeon (Slot 2). WTX power supplies are larger in size and have stronger power supply capabilities than ATX power supplies, commonly used in servers and large computers. WTX power supplies belong to one of the IA server power supply architectures.

　　7SFX, CFX, LFX Power Supplies

　　SFX, CFX, and LFX power supplies, like WTX power supplies, can be considered variants of ATX, each with their own specifications in size and power, and are compatible with ATX series motherboards like BTX power supplies. These power supplies are standards designed to accommodate small cases without dedicated graphics cards and small volume, facilitating personal computer assembly with different cases and accessories. CFX12V is suitable for cases with a system volume of 10 to 15 liters; LFX12V is suitable for cases with a system volume of 6 to 9 liters, available in 180W and 200W specifications; SFX power supplies measure 125x100x63.5mm.