Best PC Power Supplies Under $100: 7 Spec-Based Picks

Quick picks

The best fit for you

• You need modern ATX 3.1 power with 850W capacity. Corsair RM850x 850W Fully Modular ATX 3.1 PSU It provides an 850W output with native PCIe 5.1 support and a 12V-2x6 connector.
• You need the highest wattage for a demanding build. Corsair RM1000e 1000W ATX Power Supply It supplies 1000 watts of power alongside an 80 Plus Gold efficiency rating.
• You want a white power supply with ATX 3.1. Corsair RM850x Shift 850W White ATX Power Supply This unit features a white enclosure, ATX 3.1 standard support, and 850 watts of output.
• You are building a compact Mini ITX system. FSP 400W Gold Flex ATX Mini ITX Power Supply Its Mini ITX form factor measures 1.6 inches wide and provides 400 watts of power.

Our 7 picks

1 Also great

Corsair RM850x 850W Fully Modular ATX 3.1 PSU

Best for: modern ATX builds needing 850W capacity

Wattage

850W

Efficiency Rating

Cybenetics Gold

Modularity

Fully Modular

ATX Version

ATX 3.1

PCIe Connector Type

12V-2x6

PCIe Version

PCIe 5.1

View on Amazon: Corsair RM850x 850W Fully Modular ATX 3.1 PSU (paid link)

The Corsair RM850x is an 850W ATX power supply built for modern desktop systems. It provides fully modular cabling, letting you connect only the wires your build requires. You get updated standard support via ATX 3.1 and PCIe 5.1, alongside a dedicated 12V-2x6 power connector for compatible graphics cards. This unit suits you if you need clean cable management and high-wattage hardware support in a standard ATX enclosure.

Pros

• 850W continuous power capacity
• Fully modular cable design
• ATX 3.1 and PCIe 5.1 compliance
• Dedicated 12V-2x6 connector included

Cons

• Only available in black finish
• Standard ATX size does not fit SFX cases

Good fit if

• You need an 850W power supply with a native 12V-2x6 connector.
• You want fully modular cables to simplify your interior routing.
• You require compliance with ATX 3.1 and PCIe 5.1 hardware standards.

Skip if

• You need a small-form-factor SFX power supply.
• You require a white power supply to match your case theme.

Verdict: Corsair RM850x 850W Fully Modular ATX 3.1 PSU delivers 850W of power alongside modern PCIe 5.1 and 12V-2x6 connectivity. It provides an organized, fully modular configuration for standard ATX computer cases.

2 Best premium

Corsair RM1000e 1000W ATX Power Supply

Best for: high-wattage ATX gaming and workstation builds

Wattage

1000 Watt

Efficiency Rating

80 PLUS Gold

Modularity

Fully Modular

Form Factor

ATX

Size

1000W

Dimensions

5.91 × 5.51 × 3.39 inches

View on Amazon: Corsair RM1000e 1000W ATX Power Supply (paid link)

This Corsair unit provides 1000 watts of output with an 80 Plus Gold efficiency rating in an ATX form factor. You get fully modular cabling, letting you connect only the cables your build requires. It includes dual EPS12V connectors and 105°C-rated capacitors for dependable operation. This power supply suits you if you run high-draw components and need high wattage in a standard desktop chassis.

Pros

• 1000W continuous power capacity
• 80 Plus Gold efficiency certification
• Fully modular cable configuration
• Dual EPS12V connectors included
• 105°C-rated internal capacitors

Cons

• ATX standard form factor does not fit small-form-factor SFX cases
• Available only in a black color finish

Good fit if

• You need 1000W of power for high-draw computer hardware.
• You want fully modular cables to reduce case clutter.
• You require dual EPS12V power connections for your motherboard.

Skip if

• You are assembling a compact PC that requires an SFX power supply.
• You only need lower wattage for an entry-level desktop build.

Verdict: Corsair RM1000e 1000W ATX Power Supply delivers 1000 watts of power with 80 Plus Gold efficiency and fully modular cabling.

3 Also great

Corsair RM850x Shift 850W White ATX Power Supply

Best for: white ATX 3.1 gaming PC builds

Wattage

850W

Efficiency Rating

80 Plus Gold

Modularity

Fully Modular

ATX Version

ATX 3.1

PCIe Connector Type

PCIe 5.1

Dimensions

6.3 × 5.91 × 3.39 inches

View on Amazon: Corsair RM850x Shift 850W White ATX Power Supply (paid link)

This Corsair RM850x Shift is an 850W ATX power supply featuring a white finish. It provides 80 Plus Gold efficiency along with native ATX 3.1 and PCIe 5.1 standard support. The unit features fully modular cabling to reduce clutter and includes Zero RPM mode for quiet operation at low draw. You will find it matches modern gaming rigs that need 850W output, newer power delivery standards, and matching white hardware.

Pros

• 850W output with 80 Plus Gold efficiency
• Complies with ATX 3.1 and PCIe 5.1 standards
• Fully modular cable configuration
• Zero RPM fan mode for silent operation at low loads

Cons

• White finish does not match all-black chassis builds
• 6.3-inch length requires verifying clearance in compact ATX cases

Good fit if

• You need an 850W power supply supporting ATX 3.1 and PCIe 5.1 specifications.
• You are assembling a white-themed PC and prefer fully modular cabling.
• You want Zero RPM mode to maintain silent operation under light workloads.

Skip if

• You need more than 850W of continuous power capacity.
• You have a compact case that cannot accommodate a 6.3-inch PSU length.

Verdict: Corsair RM850x Shift 850W White ATX Power Supply delivers modern ATX 3.1 and PCIe 5.1 compliance with fully modular cables and 80 Plus Gold efficiency. It provides a solid 850W foundation for clean white PC builds.

4 Best 750w

Corsair RM750x Shift White 750W ATX Power Supply

Best for: side-cable routing in compatible ATX cases

Wattage

750W

Efficiency Rating

80 Plus Gold

Modularity

Fully Modular

ATX Version

ATX 3.1

Fan Size

140mm

PCIe Version

PCIe 5.1

View on Amazon: Corsair RM750x Shift White 750W ATX Power Supply (paid link)

The Corsair RM750x Shift is a 750W ATX power supply featuring side-mounted modular connectors and an 80 Plus Gold efficiency rating. It supports modern hardware through native ATX 3.1 and PCIe 5.1 standards. Its 140mm fluid dynamic bearing fan provides cooling alongside 105°C-rated Japanese electrolytic capacitors. This unit suits you if you build inside a compatible ATX chassis and want cleaner cable management using micro-fit modular cables for your system components.

Pros

• Side-mounted modular interface simplifies cable routing
• Certified ATX 3.1 and PCIe 5.1 compliant
• 80 Plus Gold efficiency rating
• 140mm fluid dynamic bearing fan
• 100% 105°C-rated Japanese electrolytic capacitors

Cons

• Side-facing connectors require clearance behind the motherboard tray
• Uses Type 5 micro-fit cables rather than legacy modular cables
• Overall 6.3-inch length exceeds standard 5.5-inch compact units

Good fit if

• You need ATX 3.1 and PCIe 5.1 support for modern graphics hardware.
• You build in an ATX chassis with clearance for side-facing modular connectors.
• You want an 80 Plus Gold rated 750W power supply in white.

Skip if

• You have a compact case lacking side clearance for the connector interface.
• You need more than 750W of power for high-draw hardware.
• You plan to reuse standard Corsair Type 4 modular cables.

Verdict: Corsair RM750x Shift White 750W ATX Power Supply provides 80 Plus Gold efficiency, modern ATX 3.1 compliance, and innovative side-mounted connections. It delivers reliable 750W power delivery for compatible PC enclosures.

5 Best 500w

EVGA 500 W1 500W Power Supply

Best for: entry-level 500-watt PC builds

Wattage

500W

Efficiency Rating

80+ WHITE

Dimensions

5.51 × 5.91 × 3.35 inches

Weight

4 pounds

View on Amazon: EVGA 500 W1 500W Power Supply (paid link)

The EVGA 500 W1 500W Power Supply delivers 500 watts of output for basic desktop systems. It carries an 80 Plus White efficiency rating, maintaining at least 80 percent efficiency under typical operating loads. The chassis measures 5.51 inches long and weighs 4 pounds. Integrated circuitry provides OVP, UVP, OCP, OPP, and SCP safety protections when you assemble entry-level hardware.

Pros

• 80 Plus White certified with 80% or higher efficiency under typical loads
• Heavy-duty protections including OVP, UVP, OCP, OPP, and SCP
• Compact 5.51-inch length fits standard cases
• 500-watt capacity handles basic system loads

Cons

• 80 Plus White rating provides lower efficiency than Bronze or Gold units
• 500W output limits support for high-power graphics cards

Good fit if

• You need 500 watts of power for a basic desktop configuration.
• You want full standard protections including OVP, UVP, OCP, OPP, and SCP.

Skip if

• You require higher efficiency ratings such as 80 Plus Gold.
• You need more than 500 watts of capacity for demanding components.

Verdict: EVGA 500 W1 500W Power Supply provides baseline 500-watt power delivery with complete multi-point circuit protection. It serves basic desktop configurations needing an 80 Plus White unit.

6 Best mini itx

FSP 400W Gold Flex ATX Mini ITX Power Supply

Best for: compact Mini ITX and NAS system builds

Wattage

400W

Efficiency Rating

80 Plus Gold

PCIe Connector Type

6+2 pin

Fan Size

4 cm

Form Factor

Mini ITX

Dimensions

5.9 × 1.6 × 3.25 inches

View on Amazon: FSP 400W Gold Flex ATX Mini ITX Power Supply (paid link)

This is a compact Flex ATX and Mini ITX power supply from FSP designed for small chassis, NAS setups, and compact systems. You get a 400W capacity rated at 80 Plus Gold efficiency, delivering over 90 percent efficiency under load. It features a single 6+2 pin PCIe connector, a 4 cm cooling fan, and dimensions measuring 5.9 by 1.6 by 3.25 inches to fit restricted spaces.

Pros

• 80 Plus Gold certified with efficiency exceeding 90%
• Compact dimensions of 5.9 by 1.6 by 3.25 inches
• Includes one 6+2 pin PCIe connector for a graphics card
• Rated for 100,000-hour MTBF at 25°C and 50°C burn-in testing

Cons

• Limited to 400W total capacity
• Offers only one 6+2 pin PCIe power connector
• Uses a small 4 cm internal cooling fan

Good fit if

• You build in a compact Mini ITX, NAS, or Flex ATX enclosure.
• You want 80 Plus Gold efficiency in a 400W unit.
• You need a single 6+2 pin PCIe connection for a dedicated card.

Skip if

• You require more than 400W of total output.
• You use hardware needing multiple PCIe power connectors.

Verdict: FSP 400W Gold Flex ATX Mini ITX Power Supply delivers 80 Plus Gold efficiency in an ultra-compact footprint designed for space-restricted builds. Its 400W rating and single PCIe connection cover low-power Mini ITX and NAS hardware requirements.

7 Also great

CableMod C-Series Pro ModMesh Cable Kit

Best for: Corsair Type 4 power supply builds

Dimensions

3.94 × 3.94 × 3.94 inches

View on Amazon: CableMod C-Series Pro ModMesh Cable Kit (paid link)

This is a modular replacement cable kit designed specifically for Corsair Type 4 power supplies, including RM Black Label, RMi, and RMx units. It provides you with high-density ModMesh sleeving, thicker wire construction, and pre-installed closed cable combs in a black finish. It suits you if you already own a compatible Corsair power supply and want neat direct-to-unit cabling without the extra length of extensions.

Pros

• High-density ModMesh sleeving
• Pre-installed closed cable combs
• Thicker wires for a fuller profile

Cons

• Only compatible with Corsair Type 4 pinouts
• Provides accessory cables rather than a standalone power supply

Good fit if

• You use a Corsair Type 4 RM Black Label, RMi, or RMx unit.
• You want direct replacement cables with pre-installed combs.

Skip if

• You need an actual power supply unit for a new build.
• You use a power supply that does not share Corsair Type 4 pinouts.

Verdict: CableMod C-Series Pro ModMesh Cable Kit delivers direct-connect replacement wiring with pre-installed combs for compatible Corsair units. It organizes your setup efficiently if you already run a supported Type 4 power supply.

Specifications side by side

Specification Trade-Offs in Under $100 Models

When you shop Under $100, hardware configurations show clear boundaries across efficiency ratings and modern standards. Most higher-wattage units provide 80 Plus Gold efficiency and fully modular cabling, but maximum efficiency tops out here. Entry-level units drop to 80 Plus White ratings and omit modular designs. Compact Mini ITX choices remain limited to lower capacities like 400W. Additionally, modern ATX 3.1 specifications and PCIe 5.1 connectors are absent on select high-wattage and baseline units. You must balance wattage capacity against newer connector standards and modular cable layouts.

• Efficiency Rating: Options reach 80 Plus Gold at most, while lower-tier units drop to 80 Plus White.
• ATX Version: Modern ATX 3.1 and PCIe 5.1 standards are absent on select high-wattage and baseline models.
• Form Factor: Mini ITX power supplies in this group top out at 400W.
• Modularity: Fully modular cable management is not available on entry-level models.

How We Picked These Units

You see Amazon listings that match the Under $100 range. We evaluate each unit strictly using specifications and feature lists published on the listings. Products are not physically handled. You see only one size or variant from each product family to keep your options clear.

We show products in stock first, then by Amazon sales rank (better-selling products first). Listings and availability update at least daily on the page. Items enter or leave this guide whenever they move into or out of the Under $100 range. This system ensures you always review current hardware based entirely on published technical details.

How to Choose the Right Power Supply

1. Sizing Total Wattage

   Calculate the total power draw of your components before you decide on capacity. Entry-level desktop systems with basic integrated graphics or modest discrete cards operate reliably on a lower threshold. For these systems, the EVGA 500 W1 500W Power Supply delivers adequate baseline wattage without excess overhead. High-demand graphics cards and multi-core processors draw significantly more energy under peak loads. Selecting a unit with insufficient capacity triggers shutdowns during gaming or rendering workloads. Match your estimated hardware wattage closely to the continuous output rating.

2. Dedicated GPU Power Connectors

   Inspect the power connector requirements of your dedicated graphics card before buying. Modern high-performance video cards rely on direct high-power interfaces to prevent cable clutter and ensure stable delivery. The Corsair RM850x 850W Fully Modular ATX 3.1 PSU includes a dedicated 12V-2x6 connector built for PCIe 5.1 hardware. If you use an older or lower-tier card, standard 8-pin or 6-pin PCIe cables remain necessary. Check the connector bundle listed in the specifications to verify your card connects directly without third-party adapters.

3. Cable Modularity Choices

   Evaluate the cable management space inside your computer case. Non-modular power supplies permanently attach all wiring looms, forcing you to tuck unused bundles into drive bays or lower chambers. Fully modular units let you plug in only the specific cables your components require. The Corsair RM1000e 1000W ATX Power Supply features a fully modular interface, which simplifies installation and keeps internal chassis airflow clear. If you build in a compact or windowed case, choosing modular connections eliminates unnecessary clutter and streamlines routing paths.

4. Side Terminal Clearance

   Check the orientation of the modular interface relative to your chassis layout. Traditional power supplies place modular sockets on the back end facing the internal drive cage. Side-mounted terminal designs redirect ports to the side panel for easier plug access. The Corsair RM750x Shift White 750W ATX Power Supply uses this layout to ease cable access after the unit is secured. However, you must confirm your case offers sufficient clearance behind the side panel. Narrow cases cannot accommodate the bend radius of side cables.

5. Aftermarket Cable Compatibility

   Verify modular pinouts before purchasing custom or replacement wiring kits for your build. Power supply manufacturers use proprietary wiring configurations at the unit side, even when the component ends follow ATX standards. The CableMod C-Series Pro ModMesh Cable Kit is designed specifically for Corsair Type 4 power supplies. Mixing cables across incompatible units can damage internal hardware or trigger short circuits. If you plan to replace stock cables for aesthetics or routing flexibility, match the aftermarket kit directly to the supported pinout specification of your power supply.

6. Checking Enclosure Dimensions

   Measure the power supply mounting compartment in your computer case before selecting a model. Standard ATX cases accommodate typical ATX dimensions, but specialized enclosures require smaller footprints. The FSP 400W Gold Flex ATX Mini ITX Power Supply measures 5.9 inches long and 1.6 inches wide, fitting compact server and Mini ITX enclosures. Installing an oversized unit blocks intake fans, obstructs drive cages, or prevents panel closure. Always verify physical height, width, and depth against your enclosure clearance limits to guarantee adequate physical installation space.

Frequently asked questions

See also

• best PC power supplies under 50
• best 80 Plus Gold PC power supplies
• fan under 100
• headphones under 100