Intel Core Ultra 9 285K socket: LGA 1851
The Intel Core Ultra 9 285K uses the LGA 1851 socket. It is the 24-core Arrow Lake flagship for enthusiast desktops, needing an 800 series DDR5 motherboard.
- Socket
- LGA 1851
- Launched
- October 24, 2024
- Cores and threads
- 24 and 24
- Base power
- 125 W
- Codename
- Arrow Lake
- Segment
- Desktop
- Family
- Intel Core Ultra 9
- Clocks
- 3.7 / 5.7 GHz
Intel Core Ultra 9 285K specifications
| Cores | 24 (8 Performance-cores and 16 Efficient-cores) |
|---|---|
| Threads | 24 (no Hyper-Threading) |
| Core architecture | Lion Cove (P-cores) and Skymont (E-cores) |
| P-core clocks | 3.7 GHz base, up to 5.5 GHz turbo, 5.7 GHz with Thermal Velocity Boost |
| E-core clocks | 3.2 GHz base, up to 4.6 GHz turbo |
| Cache | 36 MB Intel Smart Cache (L3) and 40 MB total L2 |
| Processor base power (TDP) | 125 W |
| Maximum turbo power | 250 W |
| Manufacturing process | TSMC N3B (compute tile) |
| Memory support | DDR5 up to 6400 MT/s, two channels, up to 256 GB |
| PCI Express | 24 lanes from the CPU: PCIe 5.0 and PCIe 4.0 |
| Integrated graphics | Intel Graphics, 4 Xe-cores, up to 2.0 GHz |
| NPU | Intel AI Boost, 13 TOPS |
| Multiplier | Unlocked (K series) |
| ECC memory | Supported on platforms that enable it |
| Package | FCLGA1851, 45 × 37.5 mm |
| Cooler in the box | None |
| Launch price | $589 (tray) or $599 (boxed), Intel recommended customer price |
Motherboard and chipset compatibility
Intel Core Ultra 9 285K needs a motherboard with a LGA 1851 socket. The table shows which chipset series accept it.
| Series | Chipsets | Support |
|---|---|---|
| 800 series | Z890, B860, H810, Q870, W880 | Works out of the box |
Board makers publish a CPU support list for every model. Check it for your exact board before buying. Chipset details for LGA 1851.
Recommended GPU pairing
| Recommended tier | Flagship 4K |
|---|---|
| Example GPUs | GeForce RTX 5090, Radeon RX 7900 XTX |
| Target resolution | 4K high settings |
Twenty-four cores with boost to 5.7 GHz, 24 PCIe lanes with PCIe 5.0 graphics and DDR5-6400 feed flagship 4K cards from its era. The RTX 5090 from January 2025 and the RX 7900 XTX from December 2022 match that class at 4K high settings.
This is a rough match for a new build at the stated resolution, not a limit. A faster card still works and helps at higher resolutions or in games that load the GPU more than the CPU. A slower card is fine for lighter games and office use. The exact balance shifts with the game, the settings and the resolution, so no percentage is given.
LGA 1851 at a glance
| Type | LGA, 1,851 contacts |
|---|---|
| Package size | 45.0 × 37.5 mm |
| Introduced | October 2024 |
| Memory | DDR5 only |
| Cooler mounting holes | 78 × 78 mm |
What the Core Ultra 9 285K is
The Core Ultra 9 285K is the flagship desktop processor of Intel's Core Ultra 200S family, released in October 2024 under the codename Arrow Lake. It has 8 Performance-cores and 16 Efficient-cores for 24 cores and, with no Hyper-Threading, 24 threads. Performance-cores run 3.7 GHz base to 5.5 GHz turbo, reaching 5.7 GHz with Thermal Velocity Boost, while Efficient-cores run 3.2 GHz to 4.6 GHz. The 36 MB L3 cache is shared with 40 MB of total L2.
Intel rates the base power at 125 W with maximum turbo power at 250 W. The compute tile uses TSMC N3B, a first for Intel desktop silicon, and the package measures 45 × 37.5 mm. Integrated Intel Graphics with 4 Xe-cores up to 2.0 GHz cover display output, and an Intel AI Boost NPU adds 13 TOPS.
The launch price was $589 tray or $599 boxed, and the K suffix marks the unlocked multiplier. Intel includes no cooler with K-series processors.
Socket and motherboard compatibility
The 285K goes into an LGA 1851 socket. Only motherboards with 800 series chipsets (Z890, B860, H810, Q870, W880) carry it. The chip is not compatible with the 600 and 700 series boards of LGA 1700, and it will not fit them.
Z890 boards unlock the multiplier for K-series overclocking, while B860 and H810 run rated clocks with memory tuning. The 285K launched beside Z890, with the other 800 series chipsets following in early 2025.
LGA 1851 boards take DDR5 only, so DDR4 modules from older systems cannot transfer. Intel specifies DDR5-6400 across two channels to 256 GB with ECC support on enabled platforms.
Memory, PCIe and cooling
The processor provides 24 PCIe lanes split between PCIe 5.0 and 4.0: a x16 graphics link with additional x4 links for NVMe storage, configurable per board. The chipset adds further lanes for devices and networking.
Cooling must handle 125 W base and up to 250 W turbo during heavy all-core loads, so a capable air cooler or liquid cooler is the realistic choice. Mounting holes keep the 78 mm pattern shared with LGA 1700, so many LGA 1700 coolers carry over with maker approval. The CPU cooler compatibility by socket guide covers the patterns.
Memory overclocking through XMP profiles works on supporting boards, and the NPU accelerates local AI features in Windows and creation apps without loading the CPU or GPU.
Cores, threads and NPU
Arrow Lake drops Hyper-Threading, so each core runs one thread and scheduling turns simpler: 24 cores means 24 threads with no thread pairing behavior to manage. The Skymont Efficient-cores carry more of everyday and background work than prior generations, while Lion Cove Performance-cores take latency sensitive foreground tasks.
The integrated NPU with 13 TOPS, 36 TOPS overall across CPU, GPU and NPU, covers Copilot+ style local AI with 16 GB or more of memory. The 4 Xe-core integrated graphics drive displays and accelerate media without a discrete card.
Against the previous 14th Gen flagships the design trades thread count and peak power for efficiency, which suits builders who want high performance without extreme cooling.
Upgrade paths
Within LGA 1851 the 285K is the top option, with the Core Ultra 7 and 5 below it for smaller budgets. Coming from 14th Gen chips such as the Intel Core i9-14900K, the move needs a new board and DDR5 memory.
Intel's next desktop generation is reported to use a different socket, so LGA 1851 may not extend past the current family. Compare AM5 from AMD, where the maker stated support through 2029, when long upgrade paths matter.
Frequently asked questions
What socket does the Intel Core Ultra 9 285K use?
It uses LGA 1851, written FCLGA1851 in Intel's documents.
Can the 285K run in an LGA 1700 motherboard?
No. LGA 1851 is a different socket with different chipsets, and the processor does not fit Z790 or Z690 boards.
Does the 285K support DDR4?
No. LGA 1851 boards use DDR5 only.
Does the 285K have Hyper-Threading?
No. It has 24 cores and 24 threads, one thread per core.
Does the 285K come with a cooler?
No. Intel does not bundle a cooler with K-series processors.
Sources and verification
Facts last checked against these sources on . Page last edited on .