Every part of a gaming PC that draws power turns it into heat, and cooling’s job is to move that heat out of the case quickly enough for the parts to keep running. There is no single best CPU cooler. The right choice depends on the heat your processor produces, what fits in your case, how much noise you accept and how much upkeep you want. Mounting, orientation, memory clearance and noise figures are model-specific, so this guide shows what a notice says for two documented models and tells you where to read the notice for yours.

Gimaxo has not tested any cooler, so this guide names no best model and quotes no prices. The two models below are examples whose makers’ pages were read on November 6, 2026. They are not recommendations. Where a sentence starts with “Our reading:”, it is this guide’s own conclusion, drawn from the source named just before it.

Illustration of an open case with a tower air cooler, not a photograph of a real build.

Know how much heat you are dealing with

Start with the processor, not the cooler. Read the processor maker’s page for the exact model. AMD lists a maximum operating temperature of 95°C for the Ryzen 7 9800X3D and Ryzen 7 9850X3D, and it also lists a recommended cooler: “Liquid cooler recommended for optimal performance”. That is a recommendation on the product page, and the pages Gimaxo read do not call it a requirement. Intel lists a base power of 125 W and a maximum turbo power of 250 W for the Core Ultra 9 285K, with a thermal solution specification of PCG 2020A. These are advertised figures, and our guide to processor specifications explains how they differ from measured power.

Cooler makers publish their own ratings. Noctua’s page for the NH-D15 G2, for example, lists its own NSPR rating of 228 and points to a compatibility tab for the CPU performance it expects. Compare such ratings cautiously.

Air coolers: one documented example

A tower air cooler carries heat from the CPU through a base plate into heat pipes, spreads it across a stack of fins and uses fans to push air through them. Noctua’s page for the NH-D15 G2 lists, as of November 6, 2026:

• Size: 168 mm tall, 150 mm wide and 152 mm deep with its two 140 mm fans.
• Sockets: AM5, AM4, LGA1700, LGA1851, LGA1954, LGA1156, LGA1155, LGA1150, LGA1151 and LGA1200.
• Fans: two NF-A14x25r G2 fans, 0 to 1500 rpm. Noctua lists a maximum acoustical noise of 24.8 dB(A) for the fan. That is a value Noctua announces for the fan, in test conditions the page text does not state. It is not the noise your PC will make, and it is not a guarantee. Two Low-Noise Adaptors are in the box.
• Warranty: 6 years.

Memory clearance is where this model’s rules show. Noctua says the NH-D15 G2 allows RAM modules up to 32 mm tall in its default configuration, at the 168 mm height. For taller modules, its FAQ gives three options. Moving the front fan up by 3 mm for 35 mm modules raises the cooler to 171 mm. Fitting a 120 mm fan allows up to 52 mm modules at 168 mm. Removing the fan above the memory leaves 59 mm of room under the heatsink and, Noctua says, slightly decreases cooling performance.

These are the NH-D15 G2’s rules. Noctua’s own clearance chart gives other coolers different values, from “100% RAM compatibility” for some models to 66 mm for others. Our reading: take the clearance, height and fan options from the notice of the exact cooler you plan to buy, and do not carry one model’s figures over to another.

AIO liquid coolers: one documented example

An all-in-one, or AIO, cooler has a block on the CPU, sealed tubes and a radiator with fans. The page for the Arctic Liquid Freezer III Pro 280 Rev 3 (read November 6, 2026) shows what a model’s notice can contain:

• Sockets: AM5 and AM4, LGA1851 and LGA1700.
• Cables: a single PWM connector that controls the pump, the voltage-regulator fan and the radiator fan together, or a three-connector cable for individual control. The individual option needs three 4-pin headers on the motherboard.
• Order of work: the page says to connect the PWM control cable before mounting the cooler on the motherboard, and to make sure the headers are set to PWM instead of DC control.
• Airflow direction: three options are listed: Air Exhaust (pre-assembled), Air Intake (Pull) and Air Exhaust (pull). The radiator installation follows the direction you choose.
• Orientation: the page shows mounting examples labelled “Radiator below pump” and “Radiator above pump”, and a note “Risk of bubbling noise”. The page text does not give a written rule saying which layout the note refers to, so Gimaxo cannot state one. Read the pictures in your model’s notice.

Our reading: an orientation rule such as the radiator’s position against the pump belongs to the model that documents it. A different AIO may place the pump differently or give another rule, so follow the notice of your model and do not treat one maker’s page as a universal rule.

Liquid is not automatically better

An AIO is a different design, not an upgrade by definition, and an air cooler is not a lesser one. What differs is what must be checked: the air cooler’s height and memory clearance, and the AIO’s radiator position, cable plan and mounting orientation. Our reading: choose from the fit and the notice of the exact model, and use the processor maker’s recommendation as one input, not as an obligation.

Check the fit before you buy

• CPU and socket. Check the cooler maker’s socket list for your exact processor and the mounting parts the box includes.
• Case. Check the case maker’s maximum CPU cooler height, the radiator sizes the case supports and in which positions, and the total thickness of radiator plus fans.
• Memory. Check the cooler’s stated clearance for your module height, as in the NH-D15 G2 example, and whether raising a fan adds to the total height.
• Graphics card. Check that a front or top radiator leaves room for the length of your graphics card. Card makers list the length per model, and NVIDIA’s page lists some cards as “Varies by manufacturer”.

Illustration of two layouts, not photographs of real builds.

Illustration of the clearance between a graphics card and a front radiator, not a photograph of a real build.

Airflow and noise

A cooler moves heat into the case or out of its fins, and the case has to carry it away. Use the case maker’s instructions for fan positions and radiator support, and your model’s notice for orientation. Gimaxo found no maker guidance in this pass that supports a general rule about case pressure or dust, so this guide gives none.

Noise figures are the makers’ own announced values. Noctua lists 24.8 dB(A) as the maximum acoustical noise for the NH-D15 G2’s fan, in conditions its page text does not state, and Arctic’s page carries a note about a risk of bubbling noise next to its mounting examples. Our reading: a maker’s noise value is not the noise of your PC, and two makers’ values are not comparable without a common test protocol. Check your own board’s settings for fan control, as the Arctic notice does for PWM headers.

Upkeep

Gimaxo found no upkeep guidance in the two notices read. Follow your cooler’s maker for cleaning, fan replacement and warranty terms, and compare warranties instead of assuming a lifespan. Noctua lists 6 years for the NH-D15 G2. Remounting any cooler means cleaning off and reapplying thermal paste.

CPU cooling and GPU cooling are separate problems

A graphics card ships with its own cooler, designed by the card maker, and a CPU cooler does not cool it. Our guide to graphics cards covers how to read a card’s temperature and size figures. Hybrid liquid-cooled cards and custom loops are a different category and outside this guide.

Before you buy

• Read the processor maker’s page for power, maximum temperature and any cooler listing, and remember that a listing is a recommendation.
• Check the cooler’s socket list and mounting parts for your processor.
• Check the case maker’s cooler height and radiator support, including fan thickness.
• Check memory clearance with your module height, and graphics card length.
• Follow your model’s notice for radiator and pump orientation, cable plan and fan headers.
• Compare maker noise figures only with their conditions, and compare warranty terms.

To find out whether better cooling would change your frame rate at all, start with our gaming PC performance guide.

Sources

Named here as plain text. Pages read on November 6, 2026 unless stated.

• AMD, Ryzen 7 9800X3D and Ryzen 7 9850X3D desktop processor pages
• Intel, Core Ultra 9 processor 285K specifications page
• Noctua, NH-D15 G2 specifications page
• Noctua, FAQ “What is the RAM clearance of my Noctua CPU cooler?”
• Noctua, FAQ “How can I ensure both case and RAM compatibility with my NH-D15 (G2)?”
• Arctic, Liquid Freezer III Pro 280 Rev 3 user manual page
• NVIDIA, GeForce graphics cards comparison page (length and slot entries)