Question

You've decided to build a new gaming computer and are researching which power supply to buy. Which component in a high-end gaming computer is likely to draw the most power? What factor in a power supply do you need to consider to make sure this component has enough wattage?

Answer 1

As we know, the graphics card (video card) will draw the most power in our PC with some top end graphics pulling 350W+ each. But even with several hard drives and a decent Intel or AMD CPU, a 600W power supply is sufficient for most single GPU configurations. For multi-GPU systems, we typically recommend at least an 850W PSU, with 1000W (or more) needed for dual GPU configurations.

When we choose a power supply, it’s important to select something that will not just meet your current needs, but also something that will suit you for any planned or possible upgrades.

Form factor in a power supply is the factor we need to consider to make sure video card has enough wattage. The most important power supply form factors -

ATXAlthough there are still AT form factor power supplies available for purchase, AT form factor power supplies are undoubtedly legacy products, on the way out. Even the later ATX form factor power supplies (ATX 2.03 and earlier versions) are falling out of favor. The major differences between the ATX and AT power supply form factors are:

1. ATX power supplies provide an extra +3.3V voltage rail.
2. ATX power supplies use a single 20-pin connector as the main power connector.
3. ATX power supplies support the soft-off feature, allowing software to turn off the power supply.

ATX12V

The ATX12V form factor is the mainstream choice now. There are several different versions of the ATX12V form factor, and they can be very different from one another. The ATX12V v1.0 specification added over the original ATX form factor a 4-pin +12V connector to deliver power exclusively to the processor, and a 6-pin auxiliary power connector providing the +3.3V and +5V voltages. The ensuing ATX12V v1.3 specification added on top the 15-pin SATA power connector on top of all that.

A substantial change occurred in the ATX12V v2.0 specification, which changed the main power connector from a 20-pin to a 24-pin format, removing the 6-pin auxiliary power connector. Also, the ATX12V v2.0 specification also isolated the current limit on the 4-pin processor power connector for the 12V2 rail (+12V current is split into the 12V1 and 12V2 rails). Later, the ATX12V v2.1 and v2.2 specifications also increased efficiency requirements and mandated various other improvements.

All ATX12V power supplies maintain the same physical shape and size as the ATX form factor.

EPS12V, SFX12V, and Others

The EPS12V power supply form factor utilizes an 8-pin processor power connector in addition to the 4-pin connector of the ATX12V form factor (this isn’t the only difference between these two form factors, but for most desktop computer users, knowing this should be sufficient). The EPS12V form factor was originally designed for entry-level servers, but more and more high-end desktop motherboards are featuring the 8-pin EPS12V processor power connector now, which enables users to opt for an EPS12V power supply.

The Small Form Factor (SFF) designation is used to describe a number of smaller power supplies, such as the SFX12V (SFX stands for Small Form Factor), CFX12V (CFX stands for Compact Form Factor), LFX12V (LFX stands for Low Profile Form Factor) and TFX12V (TFX stands for Thin Form Factor). They are all smaller than the standard ATX12V form factor power supply in terms of physical size, and small form factor power supplies need to be installed in corresponding small form factor computer cases.