Intel Core Ultra 200S · LGA1851 / Single-tower air cooler
Does the Thermalright Assassin X 120 R SE fit the Core Ultra 7 265K?
Physically yes, thermally no. The Thermalright Assassin X 120 R SE is rated 220 W against the Core Ultra 7 265K's 250 W boost limit, so we estimate 100 °C under sustained load, at the 100 °C throttle point.
Reviewed by Farrukh Sufyan SarwarHow we estimate temperaturesPublished Prices verified
Full load
100°
Gaming
63°
Idle
35°
Throttling risk
Throttling risk at 100 °C
0 °C below the 100 °C junction limit under a sustained all-core load.
Pairing the Core Ultra 7 265K with the Thermalright Assassin X 120 R SE leaves a 30 W deficit. Under a sustained all-core load the 250 W package power pushes our estimate to 100 °C, at the 100 °C junction limit, so clocks will drop. Gaming at around 135 W stays near 63 °C.
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 | 63 °C |
| Full load | 100 °C |
| Junction limit | 100 °C |
- 0–85 % comfortable
- 85–100 % fans ramp
- 100 %+ throttles
- Thermal headroom
- -30 W
- CPU boost / gaming draw
- 250 W / 135 W
- Cooler sustained rating
- 220 W
- Junction limit
- 100 °C
- Cooler height
- 155 mm
- RAM clearance
- Unrestricted
- Sockets in the box
- AM4 · AM5 · LGA1200 · LGA1700 · LGA1851
What the numbers mean for this build
- 01
Full-load estimate pinned at TjMax (100 °C)
At 114 % of the cooler's rated 220 W capacity, the Core Ultra 7 265K cannot sustain 250 W. The CPU will hold 100 °C and shed clock speed instead of overheating, so all-core benchmarks and renders will run below spec.
- 02
Intel PL2 sustained draw: 250 W
Most Z-series boards leave the Core Ultra 7 265K at an unlimited Tau, so 250 W is a continuous load, not a 56-second burst. A single-tower air cooler is undersized for that; either enforce Intel default power limits in BIOS or step up to a 360 mm AIO or dual-tower air cooler.
Will it physically fit?
Drag the sliders to your memory height and case limits. The schematic moves with you and shows where the Assassin X 120 R SE clashes.
This heatsink does not overhang the DIMM slots.
Listed as “CPU cooler clearance” in the case spec sheet. This cooler is 155 mm tall.
- RAM heightFits
The heatsink does not overhang the DIMM slots, so any RAM height fits.
- Cooler height vs caseFits (+10 mm)
10 mm between the cooler and the side panel.
Overall Fits for the Assassin X 120 R SE with your inputs.
Schematic, not to product scale.
Better options for the Core Ultra 7 265K
Three tiers picked for this exact CPU: the cheapest tower that passes, the quietest liquid option per dollar, and the best low-profile heatsink.
Reviewed cooler
$17.49as of Sep 17, 11:38 PM UTC · In Stock
ThermalrightAssassin X 120 R SE
Single-tower air cooler · 155 mm
220 W rated, -30 W headroom on the Core Ultra 7 265K.
Top air value
$42.39as of Sep 17, 11:38 PM UTC · In Stock
ThermalrightPeerless Assassin 140
Dual-tower air cooler · 157 mm
30 W headroom for about $50
Silent liquid pick
$53.90as of Sep 17, 11:38 PM UTC · Only 4 left in stock - order soon.
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 Sep 17, 11:38 PM UTC
ThermalrightAXP120-X67
Low-profile air cooler · 67 mm
67 mm tall; best low-profile option, but expect throttling in all-core loads
Product 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.
Cheapest upgrades with a better verdict: ID-Cooling FROZN A620 Pro SE (~$27), Thermalright Peerless Assassin 120 (~$32), Arctic Freezer 36 (~$35), Thermalright Peerless Assassin 120 SE (~$35), Arctic Freezer 36 A-RGB (~$36), Thermalright Frozen Magic 240 ARGB V2 (~$44).
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 (typically 95–100 °C, 89 °C on Ryzen X3D parts). 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.
Frequently asked questions
Will the Thermalright Assassin X 120 R SE keep the Core Ultra 7 265K from thermal throttling?
Not under sustained all-core loads. Our model estimates 100 °C against a 100 °C limit at 250 W, so the CPU will reduce clocks. Gaming loads around 135 W remain fine.
What temperature should I expect while gaming on the Core Ultra 7 265K with this cooler?
Around 63 °C with a 35 °C case ambient, because GPU-bound games only draw about 135 W from the CPU package. Cooler rooms and better case airflow lower that figure.
Does the Thermalright Assassin X 120 R SE fit tall RGB RAM?
Yes. The heatsink does not overhang the memory slots, so any module height works.
Is the Thermalright Assassin X 120 R SE compatible with the LGA1851 socket?
Yes, LGA1851 hardware is included. Supported sockets: AM4, AM5, LGA1200, LGA1700, LGA1851.
Hubs: Core Ultra 7 265K · Thermalright Assassin X 120 R SE · LGA1851