Intel Core Ultra 200S · LGA1851 / Dual-tower air cooler
Does the Thermalright Peerless Assassin 140 Digital fit the Core Ultra 9 285K?
Yes. The Thermalright Peerless Assassin 140 Digital fits the Core Ultra 9 285K with 30 W of thermal headroom; we estimate 89 °C under sustained load and 61 °C while gaming, an excellent match.
Reviewed by Farrukh Sufyan SarwarHow we estimate temperaturesPublished Prices verified Model v1.2 · data updated
Full load
89°
Gaming
61°
Idle
35°
Excellent fit
Safe at 89 °C full load
11 °C below the 100 °C junction limit under a sustained all-core load.
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The Thermalright Peerless Assassin 140 Digital is an excellent match for the Core Ultra 9 285K, with 30 W of headroom above its 250 W boost ceiling. We estimate 61 °C in games and 89 °C under a full all-core render, leaving quiet-fan-curve room.
Thermal estimate
Both figures assume a 35 °C case-internal ambient and the cooler's sustained rating; the CPU's own junction limit caps the full-load figure.
| Load | Estimate |
|---|---|
| Idle | 35 °C |
| Gaming | 61 °C |
| Full load | 89 °C |
| Junction limit | 100 °C |
- 0–85 % comfortable
- 85–100 % fans ramp
- 100 %+ throttles
- Thermal headroom
- +30 W
- CPU boost / gaming draw
- 250 W / 162 W
- Cooler sustained rating
- 280 W
- Junction limit
- 100 °C
- Cooler height
- 157 mm
- RAM clearance
- 42 mm
- Sockets in the box
- AM4 · AM5 · LGA1200 · LGA1700 · LGA1851
What the numbers mean for this build
- 01
30 W of sustained headroom
The Core Ultra 9 285K uses 89 % of the Thermalright Peerless Assassin 140 Digital's rated capacity at its 250 W ceiling. Fans will ramp under all-core loads but temperatures stay controlled.
- 02
Intel PL2 sustained draw: 250 W
Motherboards commonly remove the Tau window, so treat 250 W as continuous. The Thermalright Peerless Assassin 140 Digital has the mass to absorb it; enabling Intel Default Settings in BIOS still helps long-term stability on 13th/14th Gen parts.
- 03
RAM clearance 42 mm
Most heatspreader kits up to 42 mm slide under the front fan without moving it. Check the first DIMM slot on boards with the socket placed close to the memory.
Will it physically fit?
Drag the sliders to your memory height and case limits. The schematic moves with you and shows where the Peerless Assassin 140 Digital clashes.
Stock front-fan clearance on the Peerless Assassin 140 Digital: 42 mm.
Listed as “CPU cooler clearance” in the case spec sheet. This cooler is 157 mm tall.
- RAM heightClash (-2 mm)
Modules sit 2 mm too tall. Raise the front fan or choose 34 mm low-profile RAM.
- Cooler height vs caseFits (+8 mm)
8 mm between the cooler and the side panel.
Overall Clash for the Peerless Assassin 140 Digital with your inputs.
Schematic, not to product scale.
Buy it, or compare the alternatives
Three tiers picked for this exact CPU: the cheapest tower that passes, the quietest liquid option per dollar, and the best low-profile heatsink.
This pairing
$53.09as of Nov 2, 05:59 AM UTC · In Stock
(opens Amazon in a new tab)ThermalrightPeerless Assassin 140 Digital
Dual-tower air cooler · 157 mm
280 W rated, 30 W headroom on the Core Ultra 9 285K.
Top air value
$42.39as of Nov 2, 05:59 AM UTC · In Stock
(opens Amazon in a new tab)ThermalrightPeerless Assassin 140
Dual-tower air cooler · 157 mm
30 W of headroom; the best-value tower air cooler that passes on this CPU
Silent liquid pick
~$54
(opens Amazon in a new tab)ThermalrightFrozen Infinity 360
360 mm AIO liquid cooler · 52 mm
Estimated 79 °C under full load with quiet fan curves
Small-form-factor pick
$27.99as of Nov 2, 05:59 AM UTC · In Stock
ThermalrightAXP120-X67
Low-profile air cooler · 67 mm
67 mm tall; best low-profile option, but expect throttling in all-core loads
Not recommended for this CPU
DetailsProduct prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply to the purchase of this product.
Related reports
Other coolers on the Core Ultra 9 285K
- Thermalright Peerless Assassin 120 SEAcceptable fit
- Thermalright Phantom Spirit 120 SEAcceptable fit
- Noctua NH-D15Acceptable fit
- Noctua NH-D15 G2Excellent fit
- be quiet! Dark Rock Pro 5Acceptable fit
- Thermalright Assassin X 120 R SEThrottling risk
- Corsair Nautilus 360 RSExcellent fit
- Thermalright Assassin X 120 Refined SEThrottling risk
- be quiet! Pure Rock Pro 3Throttling risk
- Thermalright Frozen Infinity 240Acceptable fit
Thermalright Peerless Assassin 140 Digital on other CPUs
Terms used on this page
- Thermal headroom
- The cooler's sustained dissipation rating minus the CPU's boost power limit, in watts. Positive headroom lets fans run slower and quieter; 25 W or more is rated Excellent here.
- TjMax
- The maximum junction temperature the maker allows, typically 95–100 °C. AMD lists 90 °C for the Ryzen 7 5800X3D, 89 °C for the 7800X3D and 95 °C for the 9800X3D. At TjMax the CPU throttles clocks to stay in place; it will not overheat, but it will lose performance.
- PL1 / PL2
- Intel's two power limits. PL1 (Processor Base Power) is the sustained draw the CPU settles at; PL2 (Maximum Turbo Power) is the short-term boost ceiling. Many desktop boards run PL2 indefinitely, so a cooler must be sized for PL2, not PL1.
- Thermal throttling
- Automatic clock reduction when the CPU hits TjMax. A pairing is flagged as a throttling risk when the modelled full-load temperature reaches the junction limit or the cooler is rated 15 W or more below the CPU's boost power.
- RAM clearance
- The tallest memory module that fits under an air cooler's front fan in its stock position. Dual-tower coolers with less than 42 mm clash with tall RGB kits (typically 44 mm) unless the fan is raised.
- CPU cooler height
- The installed height of an air cooler from the motherboard, compared against the case's published CPU cooler clearance. Coolers at or above 160 mm exclude many compact Micro-ATX and tempered-glass mid-towers.
- Dual-tower air cooler
- An air cooler with two fin stacks and a fan between them (often a second in front). Highest air-cooling capacity, but the front fan overhangs the DIMM slots, which is where RAM clearance limits come from.
Frequently asked questions
Will the Thermalright Peerless Assassin 140 Digital keep the Core Ultra 9 285K from thermal throttling?
Yes. The estimated full-load temperature is 89 °C, 11 °C below the 100 °C throttle point.
What temperature should I expect while gaming on the Core Ultra 9 285K with this cooler?
Around 61 °C with a 35 °C case ambient, because GPU-bound games only draw about 162 W from the CPU package. Cooler rooms and better case airflow lower that figure.
Does the Thermalright Peerless Assassin 140 Digital fit tall RGB RAM?
Modules up to 42 mm clear the front fan in its stock position. 44 mm kits require raising the fan.
Is the Thermalright Peerless Assassin 140 Digital compatible with the LGA1851 socket?
Yes, LGA1851 hardware is included. Supported sockets: AM4, AM5, LGA1200, LGA1700, LGA1851.
Hubs: Core Ultra 9 285K · Thermalright Peerless Assassin 140 Digital · LGA1851