240mm vs 280mm AIO for Gaming: Which Size Fits?

What the size numbers mean

An all-in-one liquid cooler, or AIO, has three parts: a pump block that sits on the processor, a radiator, and fans. The radiator size is named by its length in millimeters and the fan size it pairs with. A 240mm AIO has a 240mm radiator and two 120mm fans. A 280mm AIO has a 280mm radiator and two 140mm fans.

The radiator is where the heat moves from liquid to air. A longer radiator with larger fans has more surface area and moves a larger volume of air, which gives it more heat-dissipating capacity. That is why the 280mm is generally the stronger cooler on paper. For a deeper look at how liquid cooling compares to air cooling, see the guide on air cooling vs liquid cooling for gaming.

• 240mm AIO: 2 x 120mm fans, fits most mid-tower cases
• 280mm AIO: 2 x 140mm fans, needs a wider case or a case with dedicated 280mm mounts

Radiator fit and case planning

A desktop case lists which radiator sizes it supports, often as a set of mounting positions on the front, top, or side panel. A case that supports a 240mm radiator will usually accept a 280mm only if the mounting holes and the case width line up. The 280mm radiator is about 40mm wider, so it does not fit every mid-tower.

Before you choose, measure or look up the case's radiator support. Tower size class is a rough guide, but the precise mounting pattern matters more. A compact or mid-tower case may have room for a 240mm on top but not a 280mm. A full-tower or a case built for large radiators is more likely to list 280mm support. For more on case sizing, read what case size is right for a gaming PC.

Some cases also position the radiator to interfere with tall memory modules or the motherboard's top mount points. A 280mm radiator in the top position sits lower, so it can crowd tall memory or the top-facing connectors. A 240mm radiator in the same position leaves more clearance. If you are building a quiet gaming PC, the larger fans of a 280mm can spin slower, which may reduce noise. See how to choose a gaming PC for quiet operation.

Fan capacity and your case airflow

The two radiator sizes differ in air volume as well as surface area. A pair of 140mm fans moves more air at a lower rotation speed than a pair of 120mm fans doing the same job. For a gaming PC that also uses the case's front or top fans, the 280mm setup shares the airflow job with fewer fans.

If the case has good airflow, either size can keep a processor under control for typical gaming sessions. If the case is a compact tower with restricted intake, a 240mm may fit more easily and still provide solid cooling. The 280mm needs the case to draw in enough air to feed its larger radiator. For a prebuilt gaming PC, the manufacturer chooses the cooler size based on the case. Browse best prebuilt gaming PCs to see common configurations.

AIO features to compare

Beyond the radiator size, an AIO's specification sheet lists the pump type, the fan speed range, and the tube length. Tube length matters for mounting orientation, especially in a larger tower where the radiator goes at the front and the pump must reach the processor.

Look for the radiator's stated thickness as well. A thicker radiator has more internal channels, but it also needs more case clearance. The mounting hardware should list which processor sockets the cooler supports, so the AIO works with your motherboard's socket.

A 240mm AIO is the common choice for a mid-tower gaming PC, while a 280mm suits a larger case or a build that prioritizes extra thermal capacity. The decision is almost always about the case, not about the processor. If you are considering a 360mm AIO, see the 360mm vs 280mm AIO comparison. For a full list of cooler options, check best CPU coolers for gaming.

Matching the cooler to your play style

The type of games you play and the resolution you target influence how hard the processor works, but the cooler size is more about the case and the overall system. A 240mm AIO is enough for a gaming PC that plays at 1080p or 1440p with a mid-range processor. A 280mm AIO can be a good match for a high-end build that runs at 4K or uses a processor with a higher power draw.

If you are building a gaming PC for 1440p, the cooler choice is part of the overall system balance. See best 1440p gaming PCs for examples of what comes in those builds. For a 4K gaming PC, the processor and cooler need to handle sustained loads. Browse best 4K gaming PCs to see typical cooling setups.

What to pick for your play

Questions

Does a 280mm AIO fit in a mid-tower case?

It depends on the case. Many mid-towers list support for 240mm and 280mm radiators on the front panel, but top-mount support is more often 240mm only. Check the case's radiator support list before buying.

Is a 280mm AIO always better than a 240mm for gaming?

A 280mm radiator has more surface area and larger fans, so it has more thermal capacity on paper. In a case that does not mount it correctly, a 240mm can still provide solid cooling for typical gaming. The fit is the deciding factor.

Can a 240mm AIO cool a high-end processor for gaming?

Yes, a 240mm AIO can handle a high-end processor in a typical gaming workload when the case has good airflow. The radiator size does not change the processor's power draw; it changes how much heat the cooling loop can move.

What matters most when choosing between 240mm and 280mm?

The case's mounting support and the clearance for tall memory. The 280mm needs a wider mounting area, and the 240mm fits more standard mid-towers.

Do I need a 280mm AIO for a gaming PC that also streams?

Streaming adds load to the processor, but a 240mm AIO in a well-ventilated case is usually sufficient. The choice depends more on the case size and the processor's power draw. See best gaming PCs for streaming for examples.

Can I mount a 280mm AIO on the front of a mid-tower?

Yes, if the case has front mounting points for a 280mm radiator. Many mid-towers support 280mm on the front but not on the top. Check the case specifications.