Last updated: September 1, 2026

Motherboard standoffs are some of the smallest components in a PC build, but installing one in the wrong place can stop an otherwise perfectly good system from working.

They are the small spacers between the motherboard and the metal motherboard tray inside the case.

The motherboard does not normally sit directly against that metal tray. Instead, its mounting holes sit on top of the standoffs and screws secure the board to them.

Their job is simple:

• keep the underside of the motherboard clear of the chassis,
• mechanically support the PCB,
• keep the rear I/O and PCIe slots at the correct height,
• and provide chassis grounding at the intended metal mounting points.

What is a motherboard standoff?

A traditional motherboard standoff is a small hexagonal spacer.

One end attaches to the motherboard tray. The other end contains a threaded hole that accepts the motherboard screw.

Once installed, the motherboard rests on top of those spacers instead of directly against the chassis.

Why can’t the motherboard touch the metal case?

The underside of a motherboard is not an electrically inert plastic surface.

It contains:

• solder joints,
• vias,
• component leads,
• test points,
• and conductive PCB structures.

The chassis tray is conductive metal.

Letting unintended points on the motherboard touch the chassis can therefore short electrical nodes that were never designed to be connected.

The ATX and Micro-ATX mechanical specifications specifically warn against having chassis standoffs in locations not defined for the motherboard because motherboard traces can be damaged.

Do metal motherboard standoffs ground the motherboard?

Yes, metal mounting hardware can form part of the motherboard-to-chassis grounding/bonding system.

For example, current Supermicro installation documentation recommends metal mounting fasteners because they ground the motherboard to the chassis.

But the old version of this article describes the process too dramatically.

A standoff is not a special emergency conductor whose purpose is to catch an electrical fault and route it through the power supply.

Think of its electrical role as intentional chassis bonding at designated motherboard ground points. Its equally important mechanical role is maintaining the correct spacing between the PCB and chassis.

For a current manufacturer example, see Supermicro’s motherboard installation documentation .

Where should motherboard standoffs go?

This is easier than memorizing ATX hole names.

Look at the mounting holes in your exact motherboard.

Every removable metal standoff beneath the PCB should align directly with one of those holes.

If there is a case standoff but no motherboard hole above it: remove or move that standoff.

If there is a motherboard mounting hole with no support underneath and your case provides a matching standoff position, add a standoff there.

ATX vs Micro-ATX vs Mini-ITX standoff positions

The mainstream form factors deliberately share mounting locations.

That is why a Mini-ITX or Micro-ATX motherboard can normally be installed inside an ATX case that officially supports the smaller form factor.

Swipe → to see the full table

The original Intel ATX specification defined the standard ATX mounting locations, while the Micro-ATX specification deliberately reused many ATX positions.

ASRock’s own support documentation also shows exactly this overlap when explaining how to install a Micro-ATX board in an ATX/mATX chassis.

See: ASRock’s ATX and Micro-ATX mounting-hole guide .

How many motherboard standoffs do you need?

The safest answer is: one for every intended mounting hole on your exact board, assuming the case provides the corresponding mounting point.

A full-size standard ATX motherboard usually has nine.

Mini-ITX normally has four.

Micro-ATX is less useful to summarize with one number because the specification allows smaller board designs to use a subset of the standard mounting positions.

Do standoffs come with the case or the motherboard?

For a normal DIY desktop, the motherboard mounting hardware normally comes with the case.

That makes sense because the case manufacturer knows:

• the thread used in its motherboard tray,
• the required standoff height,
• which positions are pre-installed,
• and which motherboard screws fit the provided standoffs.

Corsair’s current case installation instructions, for example, tell users to align the board with the chassis standoffs and secure it using the supplied screws.

See Corsair’s current motherboard installation instructions .

Pre-installed, removable and integrated standoffs

Cases do not all handle motherboard mounting in exactly the same way.

What if the center standoff has no screw hole?

That may be intentional.

Some cases use a central locating peg rather than a threaded standoff. Its job is simply to locate and support the motherboard while you install the surrounding screws.

If the peg aligns with a proper motherboard mounting hole, you normally leave it in place.

Do not drill it out or replace it merely because you cannot insert a screw.

Always check the case manual if the mounting design is unfamiliar.

Motherboard standoff screw sizes: #6-32 vs M3

PC hardware commonly uses both #6-32 UNC and M3 threading.

Motherboard standoffs frequently use #6-32 threading, but case designs vary and mixed-thread standoffs exist.

For example, some hardware can use one thread where the standoff attaches to the tray and another thread for the screw that enters the top.

The old article suggests that you can reliably identify the thread by comparing the visible lengths of different sections of the standoff.

I would remove that advice.

Standoff body length, male-thread length and female thread can vary by case and manufacturer.

Instead:

1. Check the case accessory list or manual.
2. Use the screws labeled for motherboard installation.
3. Compare with an original known-good standoff if replacing one.
4. Never force a screw that does not thread smoothly.

Does standoff height matter?

Yes.

The spacer height determines how far the motherboard sits above the tray.

Use a replacement that is too short or too tall and you can create:

• misaligned rear I/O,
• PCIe card bracket misalignment,
• stress or bowing in the motherboard,
• uneven support,
• or an incorrect distance from the tray.

Historical ATX specifications define minimum clearance requirements, but that does not mean any standoff above the minimum is suitable for any case.

How to install motherboard standoffs correctly

1. Turn the system completely off. Disconnect the PSU from AC power before working inside the case.
2. Lay the case flat with the motherboard tray facing up. This keeps the motherboard from sliding while you align it.
3. Check whether the rear I/O shield needs to be installed first. Many modern boards have an integrated I/O shield; older or cheaper boards may use a separate shield.
4. Identify the motherboard form factor and actual mounting holes. Do not rely on the form-factor label alone.
5. Inspect every pre-installed standoff. Remove or move any standoff that will sit underneath solid PCB instead of a mounting hole.
6. Add any missing standoffs. Use the standoff positions that correspond to your motherboard holes.
7. Make sure every removable standoff is secure and level. Use the case’s standoff tool/socket if provided. Do not overtighten.
8. Lower the motherboard carefully into the case. Align the rear I/O and then lower the mounting holes over the standoffs.
9. Check every hole before installing screws. All intended holes should line up without forcing or bending the PCB.
10. Start the screws loosely. Begin with the locating/center area if appropriate, or use two opposite positions to hold alignment.
11. Install the remaining screws. Do not fully tighten one corner before the others have started.
12. Tighten until snug—not excessively tight. The screw needs to secure the board, not crush the PCB.

How tight should motherboard screws be?

Snug.

A motherboard screw should hold the PCB securely against the standoff without allowing the board to move.

It should not be tightened as hard as possible.

Excessive torque can:

• strip the standoff,
• strip the motherboard tray,
• damage the screw head,
• damage the board around the mounting point,
• or make removal unnecessarily difficult.

Current Supermicro installation documentation, for example, sets an 8 lbf-in maximum for some of its boards. That does not mean you should apply that exact specification to every consumer PC; it illustrates that motherboard screws are not intended to be aggressively torqued.

Should you install every motherboard screw?

Ideally, use all of the mounting holes that the board and chassis are designed to support.

That distributes mechanical load and reduces PCB flex when:

• connecting the 24-pin ATX cable,
• installing DIMMs,
• installing M.2 drives,
• connecting front USB headers,
• or inserting expansion cards.

But do not force a screw through a hole that does not align naturally.

If one position is badly misaligned:

1. stop tightening,
2. check that the I/O area is seated correctly,
3. verify the motherboard form factor,
4. check for a misplaced standoff,
5. and confirm that you are using the correct mounting position.

What happens if one standoff is missing?

A motherboard can sometimes boot with one mounting point unsupported. That does not mean leaving it that way is good practice.

The biggest problem is mechanical.

An unsupported area of the PCB can flex when you push down on:

• the 24-pin power connector,
• RAM slots,
• USB 3.x headers,
• SATA connectors,
• or other stiff connectors near the board edge.

If your board has a proper mounting hole and your case has the corresponding standoff location, install the support.

What happens if an extra standoff is under the motherboard?

This is the more dangerous mistake.

A metal standoff sitting under solid PCB can touch an electrical point on the underside of the motherboard.

Possible symptoms include:

• the PC doing nothing when you press Power,
• instant shutdown,
• power cycling,
• failure to POST,
• debug LEDs remaining on,
• intermittent behavior when the case or motherboard is flexed,
• or, in the worst case, hardware damage.

Can an extra motherboard standoff cause a short?

Yes.

This is not just PC-building folklore.

The Micro-ATX specification explicitly states that chassis standoffs at locations not specified for ATX or Micro-ATX should be removable or omitted to avoid damaging motherboard traces.

That is why the safest final check before screwing down the board is:

look through every mounting hole and account for every standoff beneath the PCB.

Can a misplaced standoff permanently damage a motherboard?

It can.

Whether damage occurs depends on exactly what the metal standoff touches.

Sometimes a system simply refuses to power on until the short is removed. In other cases a conductive contact can damage a trace or component.

Do not repeatedly power-cycle a system after discovering a known metal-to-PCB contact.

Can you install a motherboard without standoffs?

Not directly against the normal metal motherboard tray.

The board needs the designed physical clearance from the chassis.

However, that does not mean every case must use removable brass hex standoffs.

A chassis can provide:

• pre-installed standoffs,
• integrated raised metal mounts,
• alignment pegs,
• or another manufacturer-designed mounting system.

Those still provide the required spacing and support.

What about testing a motherboard outside the case?

That is different.

During troubleshooting, builders commonly run a motherboard outside the chassis in a minimum-hardware configuration.

Place it on a suitable non-conductive surface such as the plain cardboard motherboard box.

It does not need case standoffs when it is not being installed against a metal chassis tray.

Can you use plastic motherboard standoffs?

Plastic or nylon motherboard supports exist and are used in some special chassis designs.

They can provide physical spacing but do not provide the same metal-to-chassis electrical bond as a metal mounting point.

Where the case or board manufacturer specifies metal mounting hardware, use metal hardware.

Current Supermicro documentation specifically recommends metal mounting fasteners for motherboard-to-chassis grounding.

Do you need insulating washers under motherboard screws?

Normally, no.

The motherboard’s designated mounting holes are designed for direct contact with the appropriate mounting screw/standoff hardware.

Adding nylon or insulating washers can interfere with intentional chassis grounding at those locations.

Use washers only when the motherboard or case manufacturer specifically instructs you to.

Can motherboard screws touch the metal ring around the hole?

Yes.

That metal/plated ring around a proper mounting hole is intentional.

It is not the same as a screw or standoff touching a random trace elsewhere on the motherboard.

You do not need to isolate a normal motherboard mounting screw from that ring with electrical tape or a plastic washer.

Can cables run behind the motherboard?

Yes—behind the motherboard tray.

Cable-management space behind the tray is one of the main features of a modern PC case.

What you should not do is sandwich a cable:

motherboard PCB → cable → metal tray.

A cable trapped directly underneath the PCB can:

• prevent the motherboard from sitting flat,
• apply pressure to solder joints,
• interfere with standoff height,
• or cause mounting misalignment.

What if the screw holes do not line up with the standoffs?

Do not force them.

Work through these checks:

1. Is the motherboard completely seated against the rear I/O opening?
2. Is a separate I/O shield spring tab pushing against a connector?
3. Are you using the correct motherboard form-factor positions?
4. Is one pre-installed standoff in the wrong place?
5. Is the center alignment peg preventing the board from settling?
6. Is a cable trapped beneath the PCB?
7. Does the case actually support this motherboard size?

Mini-ITX standoffs

Mini-ITX is standardized around a 170 × 170mm board and uses four mounting locations from the wider ATX/microATX family.

That makes installing one in an ATX case fairly simple:

1. identify the four Mini-ITX mounting holes,
2. leave or install only the corresponding chassis standoffs,
3. remove any other removable standoff that would sit below the board,
4. lower the board onto those four points.

The small PCB does not mean mounting support matters less.

Mini-ITX boards often place the 24-pin connector, M.2 hardware, CPU power and other stiff connectors close to the board edge, so all four mounting points are useful.

If you are planning a compact AM5 build, see our Best Mini-ITX AM5 Motherboards .

Micro-ATX standoffs

Micro-ATX has a maximum board size of 244 × 244mm, but manufacturers can make narrower Micro-ATX boards.

That means two products both marketed as Micro-ATX can have different numbers of actual PCB mounting holes.

The standard chassis can provide all the defined positions, but the board itself may use only the subset appropriate to its size.

ATX standoffs

A conventional full-size ATX motherboard measures 305 × 244mm and the ATX specification defines nine standard mounting locations.

That is why many ATX cases arrive with nine positions already prepared.

Still verify them.

Cases are designed to support multiple motherboard sizes, and a previous owner may also have moved standoffs for another board.

Back-connect motherboards still need the correct standoffs

Modern boards such as ASUS BTF, MSI Project Zero and Gigabyte Project Stealth move many power and I/O connectors to the rear of the motherboard.

That does not eliminate motherboard mounting points.

The case still needs:

• the correct motherboard form-factor mounting pattern,
• the correct standoffs,
• and additional tray cutouts that expose the rear-facing connectors.

A case can therefore support the motherboard’s size without necessarily supporting its rear-connector layout.

Corsair’s current 9000D documentation is one example of a chassis that explicitly lists support for ASUS BTF, MSI Project Zero and Gigabyte Project Stealth alongside conventional motherboards.

How to remove a motherboard standoff

If the standoff is removable, the easiest method is normally:

1. remove the motherboard first,
2. place the case where you have clear access,
3. use the case’s supplied standoff socket/tool if available,
4. or use a correctly sized nut driver/socket on the hex body,
5. turn counterclockwise gently.

Needle-nose pliers can sometimes work in an emergency, but they are much more likely to slip and scratch the case or hardware.

What if the motherboard screw and standoff spin together?

This usually means the standoff has come loose from the case tray while the motherboard screw remains tight inside it.

Do not continue spinning it indefinitely.

If the standoff is accessible from behind the motherboard tray, you may be able to hold the standoff while loosening the screw.

If it is not safely accessible, remove the other screws and gain as much controlled access as possible.

Once the motherboard is out, separate the screw and standoff away from the PCB and replace any damaged hardware.

What if a motherboard screw is stripped?

First determine what is actually stripped:

• the Phillips screw head,
• the female thread inside the standoff,
• or the standoff’s thread in the case tray.

If the screw head is damaged, use a correctly fitting screwdriver and firm downward pressure before trying more aggressive methods.

Avoid metal drilling, cutting or extraction work with the motherboard still exposed unless you are experienced and have protected the electronics from metal debris.

Should standoffs be installed hand-tight?

They should be secure enough that they do not unscrew when the motherboard screw is later removed.

Finger-tight can sometimes be enough, but using the case’s supplied standoff socket or an appropriately sized nut driver gives better control.

The goal is secure, not maximum torque.

Common motherboard standoff mistakes

Motherboard installation final checklist

• The case officially supports the motherboard form factor.
• Every removable standoff corresponds to a motherboard hole.
• No unused metal standoff remains under solid PCB.
• Every intended motherboard mounting hole has support where available.
• Standoffs are secure and the same intended height.
• No loose screws or metal debris remain inside the case.
• No cables are trapped between the motherboard and tray.
• The rear I/O is correctly aligned.
• The motherboard sits flat without bowing.
• All motherboard screws started without force.
• Screws are snug, not excessively tight.
• PCIe expansion slots align with the case brackets.

What if the PC will not start after installing the motherboard?

Do not immediately assume that the motherboard has been damaged.

Check:

1. 24-pin motherboard power,
2. CPU/EPS power,
3. front-panel power-switch connector,
4. RAM seating,
5. GPU seating and power,
6. debug LEDs,
7. and the standoff layout.

If you suspect a mounting short:

1. disconnect AC power,
2. remove the motherboard,
3. inspect every standoff position,
4. check the PCB underside for contact marks,
5. remove misplaced hardware,
6. then test again using a minimum configuration.

For the complete diagnostic process, use our How to Tell If Your Motherboard Is Dead guide .

Useful Best Motherboard Zone guides

Motherboard standoffs FAQ