The NZXT S340 Elite is a clean, compact ATX mid-tower with a glass side panel, and it still houses a lot of gaming PCs. Its limits are specific: 161mm of CPU cooler height and front radiator mounts for 240mm or 280mm. The best CPU coolers for NZXT S340 Elite builds respect both, with a safe margin. These six picks do.
Quick verdict
Buy the Thermalright Peerless Assassin 120 SE for most S340 Elite builds: a 155mm dual tower that leaves 6mm of margin under the 161mm limit, about $35 on Amazon US as of November 2026. For a hot CPU, the ARCTIC Liquid Freezer II 280 A-RGB uses the front 280mm mount, and the Noctua NH-D12L is the roomiest air fit.
| Cooler | Type | Height or radiator | Margin or mount | Fans | Best for | Amazon US, Nov 2026 |
|---|---|---|---|---|---|---|
| Thermalright Peerless Assassin 120 SE | Dual tower | 155mm | 6mm | 2 x 120mm | Best overall | about $35, 4.7 stars, 3,389 ratings |
| Thermalright Phantom Spirit 120 SE | Dual tower | 154mm | 7mm | 2 x 120mm | Seven heat pipes | about $36, 4.8 stars, 1,011 ratings |
| Cooler Master Hyper 212 Spectrum V3 | Single tower | 152mm | 9mm | 1 x 120mm ARGB | Budget glass-panel build | about $20, 4.7 stars, 991 ratings |
| Noctua NH-D12L | Low-height dual tower | 145mm | 16mm | 1 x 120mm | Most margin, tall RAM | about $100, 4.8 stars, 675 ratings |
| Thermalright Aqua Elite 240 V3 | 240mm AIO | 240mm radiator | Front mount | 2 x 120mm | Budget liquid | about $45, 4.7 stars, 506 ratings |
| ARCTIC Liquid Freezer II 280 A-RGB | 280mm AIO | 280mm radiator | Front mount | 2 x 140mm | Hot CPUs | about $100, 4.4 stars, 751 ratings |
Prices and ratings are Amazon US snapshots as of November 2026 and will change. Margins are against the 161mm limit listed by KitGuru.
How we selected these coolers
This is a research-based roundup, not a lab test. KitGuru’s S340 Elite review lists 161mm of CPU cooler clearance, front radiator support for two 140mm or two 120mm fans, a rear 120mm radiator position and a top fan position. The case ships with a top and a rear 120mm fan, and fits GPUs up to 364mm, or 334mm with a front radiator.
We chose coolers from the Amazon US data collected on November 11, 2026, that leave at least 6mm under 161mm, or fit the front 240mm or 280mm mount. We required current Intel and AMD sockets and favored large review bases.
We excluded ARCTIC’s Freezer 36 at 159mm, which leaves only 2mm, and the Noctua NH-D15 chromax.black at 165 to 168mm, which is too tall. We did not test temperatures or noise. Ranking never follows commission.
How the S340 Elite shapes your cooler choice
At 161mm, the S340 Elite is tighter than many newer mid-towers, which often list 170mm or more. That rules out the tallest dual towers but leaves the popular 150mm to 155mm class. A Noctua study of more than 100 cases found that 56 deviated significantly from their listed clearance, so a 5mm or larger margin is worth keeping.
The radiator plan is clear: the front takes a 240mm or 280mm radiator, the rear a 120mm, and the top is listed for a fan, not a radiator. A front radiator also cuts GPU length from 364mm to 334mm, so check your graphics card length before choosing liquid.
The case ships with no front fans. That matters for air coolers, which rely on fresh intake air. If you choose a tower, adding two front intake fans is the cheapest cooling upgrade you can make in this case.
The best CPU coolers for NZXT S340 Elite, reviewed
The six picks run from the best overall air tower to the 280mm AIO. Each entry covers the margin or mount, the specs we could source, socket support, pros and cons, and a buy-or-skip line. Prices are Amazon US snapshots as of November 2026, so confirm the current figure on the listing before buying.
Thermalright Peerless Assassin 120 SE
The Peerless Assassin 120 SE is the best overall pick for the S340 Elite. At 155mm, it leaves 6mm of margin, and its dual tower and two fans handle most gaming CPUs at a budget price. It suits the typical S340 Elite build with a midrange to upper-midrange processor.
Thermalright’s page lists a 125 x 110 x 155mm heatsink, six 6mm heat pipes and TL-C12C 120mm fans at 1550rpm and 25.6 dBA, with Intel LGA 115x, 1200, 1700 and 1851 plus AMD AM4 and AM5. The Amazon listing confirms two fans and 125 x 135 x 155mm with fans.
It was listed around $35 on Amazon US as of November 2026, rated 4.7 out of 5 from about 3,400 ratings. Add front intake fans so it gets fresh air, since the S340 Elite ships without them.
- Pros: 6mm margin under 161mm; two fans; broad socket support
- Cons: can overhang tall RAM; plain silver look in a glass case
Buy if you want strong air cooling that fits with margin. Skip if you want lighting on the cooler or have very tall RAM.
Thermalright Phantom Spirit 120 SE
The Phantom Spirit 120 SE is the alternative dual tower, with seven heat pipes instead of six and a 154mm height that leaves 7mm of margin. It costs about the same as the Peerless Assassin, and it suits buyers who want slightly more heat-pipe capacity at the same size.
Thermalright’s page lists 110 x 125 x 154mm, seven 6mm heat pipes and TL-C12B V2 fans at 1500rpm, with Intel LGA 115x, 1200, 1700 and 1851 plus AM4 and AM5. The Amazon listing confirms two fans rated 25.6 dBA with S-FDB bearings, and a 105 to 280W TDP figure that is a seller claim.
It was listed around $36 on Amazon US as of November 2026, rated 4.8 out of 5 from about 1,000 ratings. We have no independent head-to-head data with the Peerless Assassin, so treat them as close alternatives.
- Pros: seven heat pipes; 7mm margin; strong rating
- Cons: dual tower can crowd tall RAM; seller TDP claim is not a verified rating
Buy if you prefer more heat pipes for about the same money. Skip if the Peerless Assassin is cheaper when you shop.
Cooler Master Hyper 212 Spectrum V3
The Hyper 212 Spectrum V3 is the budget pick for glass-panel S340 Elite builds. At 152mm, it leaves 9mm of margin, and its ARGB fan adds lighting behind the glass. It suits midrange CPUs and builds where the look behind the glass matters as much as the cooling.
Cooler Master’s page lists 124 x 73 x 152mm, one 120mm ARGB fan at 650 to 1750rpm rated 71.93 CFM and 27.2 dBA, four nickel-plated heat pipes, Intel LGA 1851, 1700, 1200 and 115x plus AM5 and AM4 support, and a two-year warranty.
It was listed around $20 on Amazon US as of November 2026, rated 4.7 out of 5 from about 990 ratings. The ARGB fan needs a 5V header on the board.
- Pros: 9mm margin; ARGB lighting; slim 73mm depth for RAM
- Cons: single fan; less headroom for hot CPUs
Buy if you want lighting and value for a midrange chip. Skip if you run a hot unlocked CPU.
Noctua NH-D12L
The NH-D12L is the roomiest air fit. At 145mm, it leaves 16mm of margin, which removes any doubt about side-panel tolerance, and it is designed for 100% RAM compatibility on mainstream sockets. It suits S340 Elite builds with tall RGB RAM or owners who want Noctua’s quiet fan and warranty.
The Amazon listing gives 145mm height, an NF-A12x25r 120mm fan, five heat pipes, 100% RAM compatibility on AM4, AM5, LGA 1700, 1200 and 115x, an offset mounting option and a six-year warranty. We could not open noctua.at, which blocked the request.
It was listed around $100 on Amazon US as of November 2026, rated 4.8 out of 5 from about 680 ratings. It costs much more than the Thermalright towers for similar capacity.
- Pros: 16mm margin; full RAM clearance; six-year warranty
- Cons: expensive; single fan
Buy if you have tall RAM or want the safest air fit. Skip if budget matters, since the Thermalright towers fit too.
Thermalright Aqua Elite 240 V3
The Aqua Elite 240 V3 is the budget liquid pick for the S340 Elite’s front mount. It moves CPU heat to a 240mm radiator, removes tower height concerns and adds two front fans the case does not ship with. It suits midrange to upper-midrange CPUs in glass-panel builds.
Thermalright’s page lists TL-C12B-S V2 fans, a pump at 2800rpm and 23 dBA, Intel LGA 115x, 1200, 1700 and 1851 plus AM4 and AM5, and a three-year warranty. The Amazon listing confirms two fans at 1500rpm, 66.17 CFM and 25.6 dBA, plus 5V ARGB sync.
It was listed around $45 on Amazon US as of November 2026, rated 4.7 out of 5 from about 510 ratings. With a front radiator, GPU length drops to 334mm, so check your card.
- Pros: uses the front mount; low price; three-year warranty
- Cons: GPU length drops to 334mm; radiator dimensions not stated in text
Buy if you want liquid cooling on a budget. Skip if your GPU is longer than 334mm.
ARCTIC Liquid Freezer II 280 A-RGB
The Liquid Freezer II 280 A-RGB is the pick for hot CPUs. The S340 Elite’s front takes two 140mm fans, so a 280mm radiator is the largest it accepts, and it offers more radiator area than any 240mm option. ARCTIC backs it with a six-year warranty, matching Noctua.
The Amazon listing gives a 280mm radiator, fans at 200 to 1900rpm with A-RGB, fan cables run inside the hose sleeve, LGA 1700 compatibility, and listed sockets of Intel 115x, 1200, 1700, 2066 and 2011(-3) plus AM5 and AM4, with a six-year warranty. LGA 1851 is not listed.
It was listed around $100 on Amazon US as of November 2026, rated 4.4 out of 5 from about 750 ratings. Check the radiator thickness against the front mount, since the review we read does not list a thickness limit.
- Pros: 280mm capacity, the largest the case takes; six-year warranty; tidy cable routing
- Cons: no LGA 1851 listed; GPU length drops to 334mm; radiator thickness not checked
Buy if you run a hot CPU and want the most capacity the case allows. Skip if you plan an LGA 1851 build.
Buying guide for S340 Elite cooling
The S340 Elite’s limits are fixed and fairly tight, so planning is simple: pick a tower that leaves margin or a radiator that fits the front. These checks help you finish the build without surprises, especially around GPU length and the front panel’s missing fans.
Margin for the best CPU coolers for NZXT S340 Elite
Use 161mm as the ceiling and aim for 155mm or less. The Peerless Assassin at 155mm leaves 6mm, the Phantom Spirit 7mm, the Spectrum V3 9mm and the NH-D12L 16mm. Avoid 159mm-plus coolers such as the Freezer 36, which leave too little room for case and board tolerance.
If you already own a 158mm cooler, measure from the board to the glass before installing.
Front radiator and GPU length
A front radiator is the S340 Elite’s only 240mm or 280mm position in the specs we read. KitGuru lists GPU length dropping from 364mm to 334mm with a front radiator. Measure your graphics card and add a few millimeters for power cables if they exit at the end.
A 280mm radiator offers more area than a 240mm, but check thickness against the front panel.
Add front intake fans
The S340 Elite ships with one 120mm top fan and one 120mm rear fan, and no front fans. If you choose an air cooler, add two front intake fans so the tower gets fresh air. If you choose a front AIO, its radiator fans become the intake and no extra front fans are needed.
Keep the top fan as exhaust to remove warm air from around the CPU.
Sockets and lighting
Every pick lists LGA 1700 and AM5 support, and all except the Liquid Freezer II list LGA 1851. ARGB fans on the Spectrum V3 and Aqua Elite use 5V 3-pin headers, so check your board manual for a matching header before relying on synced lighting with the rest of the build.
Glass-panel builds benefit from a cooler that looks tidy, which is where the Spectrum V3 and AIOs stand out.
FAQ
These answers cover common S340 Elite cooling questions about height, radiators and fans. They use KitGuru’s case spec list and the cooler listings above, and we avoid temperature numbers because we did not test any of these coolers in an S340 Elite ourselves.
What is the S340 Elite’s CPU cooler limit?
KitGuru lists 161mm of CPU cooler clearance for the NZXT S340 Elite. That fits most 150mm to 155mm towers with a few millimeters to spare, but rules out tall dual towers such as the Noctua NH-D15 at 165mm to 168mm. Keep a margin of at least 5mm where you can.
Can the S340 Elite fit a 360mm AIO?
Not according to the specs we read. KitGuru lists front radiator support for two 120mm or two 140mm fans, which means 240mm or 280mm, plus a rear 120mm. The top is listed for a fan only. A 280mm AIO such as the Liquid Freezer II 280 A-RGB is the largest option.
Is a Hyper 212 enough in the S340 Elite?
For midrange CPUs, yes, provided the case has front intake fans feeding it. The Hyper 212 Spectrum V3 fits with 9mm of margin. For hot unlocked CPUs, a dual tower like the Peerless Assassin 120 SE or a 280mm AIO gives more headroom in this compact ATX case.
Does the S340 Elite need extra fans?
It ships with only a top and a rear 120mm fan, according to KitGuru, and no front intake. Adding two front intake fans is a good idea for air coolers. With a front AIO, the radiator fans serve as the intake, so no extra front fans are needed for the cooler.
Conclusion
Buy the Thermalright Peerless Assassin 120 SE. At 155mm, it clears the S340 Elite’s 161mm limit with 6mm to spare, its dual tower handles most gaming CPUs, and it costs about $35 as of November 2026. Add two front intake fans with it, and choose the Liquid Freezer II 280 A-RGB only for a hot, high-power CPU.
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