LGA 2066 socket: CPUs, chipsets and cooler fit
LGA 2066, also called Socket R4, is the Intel socket for high end desktop and workstation processors that debuted in June 2017 with Skylake-X and Kaby Lake-X. It carries 2066 contacts in a land grid array package and replaces LGA 2011-3 on the Basin Falls platform. The launch paired the socket with the X299 chipset for Core X processors and the C422 chipset for Xeon W workstation parts, while server designs based on Skylake-SP moved to a separate socket.
Quick facts
| Maker | Intel |
|---|---|
| Package type | LGA |
| Contacts | 2,066 |
| Package size | n/a |
| Introduced | June 2017 |
| Status | Legacy |
| Memory | DDR4-2933, four channels, up to 256 GB |
| PCIe from the CPU | 48 PCIe 3.0 lanes from the CPU |
| Cooler mounting holes | 80 × 80 mm |
| Replaces | LGA 2011-3 |
| Replaced by | LGA 4189 |
Overview
On the desktop side the platform centers on quad channel DDR4 and 48 PCIe 3.0 lanes from the CPU on most models. Cascade Lake-X, the last generation from 2019, runs DDR4-2933 with up to 256 GB and keeps the 48 lane count across its 10 to 18 core stack. Cooling uses Square ILM with an 80 × 80 mm pattern shared with LGA 2011, so most LGA 2011 coolers fit, while some workstation boards use Narrow ILM and need a matching bracket. The socket is legacy, with no new processors after 2019.
Compatibility on X299 turns on BIOS versions rather than the physical fit. Early X299 boards need a BIOS update with Cascade Lake-X microcode before a 10900X class chip will start, and board makers publish the minimum version per model. The reverse also matters. Most X299 boards removed Kaby Lake-X support in the BIOS versions that added Cascade Lake-X, so a board updated for the newest chips may no longer start the oldest ones. Check the board maker CPU support list before buying or flashing.
Processor generations
| Codename | Marketing name | Years | Notes |
|---|---|---|---|
| Kaby Lake-X | Core i5 and Core i7 X series | 2017 to 2018 | Two quad core models, the Core i5-7640X and Core i7-7740X. Dual channel DDR4 and 16 PCIe 3.0 lanes. Later X299 BIOS versions removed support on most boards. |
| Skylake-X | Core X 7000 and 9000 series | 2017 to 2018 | 6 to 18 cores on X299 with quad channel DDR4 up to 2666 and up to 128 GB. The 7000 series launched the socket and the 9000 series refreshed it in 2018. |
| Cascade Lake-X | 10th Gen Core X | 2019 | 10 to 18 cores with DDR4-2933, up to 256 GB, 48 PCIe 3.0 lanes and an unlocked multiplier. The last HEDT generation on the socket. |
| Skylake-W | Xeon W 2100 series | 2017 to 2018 | Workstation Xeons for C422 boards with quad channel DDR4 and up to 512 GB. Up to 18 cores with 48 PCIe 3.0 lanes. |
| Cascade Lake-W | Xeon W 2200 series | 2019 | Workstation refresh for C422 boards. Up to 18 cores with higher clocks than Skylake-W and up to 1 TB of DDR4 on some boards. |
Chipsets for LGA 2066
X299 HEDT
Intel X299 boards for Core X processors. The chipset launched in the second quarter of 2017 with Skylake-X and Kaby Lake-X.
| Chipset | Segment | Notes |
|---|---|---|
| X299 | High-end | Core X boards with quad channel DDR4 and overclocking support. |
Who the socket serves
The socket covers two groups that share pins but not boards. Core X parts such as Skylake-X and Cascade Lake-X run on X299 for creators and enthusiasts who need lanes and memory bandwidth beyond the mainstream desktop. A 10 core Intel Core i9-9900K class mainstream chip from the same era tops out at 16 PCIe lanes and dual channel memory, while a 10 core LGA 2066 chip offers 48 lanes and quad channel memory. Xeon W parts such as Skylake-W and Cascade Lake-W run on C422 for workstation builds with larger memory limits and workstation board features.
Within X299 the generations stack by core count and memory speed. Kaby Lake-X holds two quad core models with dual channel memory and 16 lanes, a narrow slice of the platform aimed at high clocks. Skylake-X spans 6 to 18 cores across the 7000 and 9000 series with quad channel DDR4 up to 2666. Cascade Lake-X closes the line with 10 to 18 cores, DDR4-2933, larger caches on the top model and DL Boost instructions for AI work. Xeon W mirrors this on C422 with its own memory and board rules.
Memory and PCIe
Core X memory control runs four DDR4 channels. Official speeds move with the generation, from DDR4-2400 and DDR4-2666 on Skylake-X to DDR4-2933 across the Cascade Lake-X stack. Capacity moved as well, from up to 128 GB on early Core X to up to 256 GB on Cascade Lake-X on boards with eight slots. The X299 chipset supports memory overclocking, so faster kits can run above the official rating where the board allows it. ECC is not supported on X299 with Core X, which separates these boards from true workstation and server platforms.
PCIe follows the same split between CPU and chipset. Most Core X chips supply 48 PCIe 3.0 lanes, enough for two full graphics slots plus NVMe storage and add in cards without the lane sharing limits of mainstream boards. The 4 core Kaby Lake-X parts are the exception with 16 lanes. The X299 chipset adds up to 24 PCIe 3.0 lanes of its own behind a DMI 3.0 link with four lanes. There is no PCIe 4.0 on this platform. Cards made for newer slots still work, but they run at PCIe 3.0 speeds.
Identifying boards and servicing builds
Desktop LGA 2066 boards are marked Socket R4 and carry the X299 chipset next to a large socket with eight memory slots on full size boards. Compact boards may carry four slots and lower capacity limits, so read the board spec sheet rather than assuming 256 GB everywhere. The physical socket matches LGA 2011 coolers on Square ILM boards, and cooler makers list shared LGA 2011 and 2066 brackets. Noctua lists both Square ILM and Narrow ILM under LGA 2066, which confirms that the bracket must match the board.
Servicing an X299 build starts with the BIOS. Confirm the installed version against the board CPU support list before seating a Cascade Lake-X chip in a 2017 board, and flash with a supported older chip where the board needs it. Boxed X series processors ship without a cooler, and the 165 W rating across Cascade Lake-X calls for a large air cooler or liquid cooler rather than a stock part. Used buyers should favor boards with a clear support list, intact socket pins and the original ILM hardware, since replacement brackets vary between Square and Narrow layouts. The cooler guide CPU cooler compatibility by socket covers pattern matching in more detail.
CPUs on LGA 2066
35 processor pages in the database, newest first.
| Processor | Cores / threads | Base / boost | TDP | Launched |
|---|---|---|---|---|
| Intel Core i9-10900X | 10 / 20 | 3.7 / 4.5 GHz | 165 W | Oct 2019 |
| Intel Core i9-10920X | 12 / 24 | 3.5 / 4.6 GHz | 165 W | Oct 2019 |
| Intel Core i9-10940X | 14 / 28 | 3.3 / 4.6 GHz | 165 W | Oct 2019 |
| Intel Core i9-10980XE | 18 / 36 | 3.0 / 4.6 GHz | 165 W | Oct 2019 |
| Intel Core i7-9800X | 8 / 16 | 3.8 / 4.5 GHz | 165 W | Oct 2018 |
| Intel Core i9-9820X | 10 / 20 | 3.3 / 4.2 GHz | 165 W | Oct 2018 |
| Intel Core i9-9900X | 10 / 20 | 3.5 / 4.5 GHz | 165 W | Oct 2018 |
| Intel Core i9-9920X | 12 / 24 | 3.5 / 4.5 GHz | 165 W | Oct 2018 |
| Intel Core i9-9940X | 14 / 28 | 3.3 / 4.5 GHz | 165 W | Oct 2018 |
| Intel Core i9-9960X | 16 / 32 | 3.1 / 4.5 GHz | 165 W | Oct 2018 |
| Intel Core i9-9980XE | 18 / 36 | 3.0 / 4.5 GHz | 165 W | Oct 2018 |
| Intel Core i9-9990XE | 14 / 28 | 4.0 / 5.1 GHz | 255 W | Oct 2018 |
| Intel Xeon W-2175 | 14 / 28 | 2.5 / 4.3 GHz | 140 W | Oct 2017 |
| Intel Core i9-7920X | 12 / 24 | 2.9 / 4.4 GHz | 140 W | Sep 2017 |
| Intel Core i9-7940X | 14 / 28 | 3.1 / 4.4 GHz | 165 W | Sep 2017 |
| Intel Core i9-7960X | 16 / 32 | 2.8 / 4.2 GHz | 165 W | Sep 2017 |
| Intel Core i9-7980XE | 18 / 36 | 2.6 / 4.2 GHz | 165 W | Sep 2017 |
| Intel Xeon W-2102 | 4 / 4 | 2.9 / 2.9 GHz | 120 W | Aug 2017 |
| Intel Xeon W-2104 | 4 / 4 | 3.2 / 3.2 GHz | 120 W | Aug 2017 |
| Intel Xeon W-2123 | 4 / 8 | 3.6 / 3.9 GHz | 120 W | Aug 2017 |
| Intel Xeon W-2125 | 4 / 8 | 4.0 / 4.5 GHz | 120 W | Aug 2017 |
| Intel Xeon W-2133 | 6 / 12 | 3.6 / 3.9 GHz | 140 W | Aug 2017 |
| Intel Xeon W-2135 | 6 / 12 | 3.7 / 4.5 GHz | 140 W | Aug 2017 |
| Intel Xeon W-2145 | 8 / 16 | 3.7 / 4.5 GHz | 140 W | Aug 2017 |
| Intel Xeon W-2195 | 18 / 36 | 2.3 / 4.3 GHz | 140 W | Aug 2017 |
| Intel Core i5-7640X | 4 / 4 | 4.0 / 4.2 GHz | 112 W | Jun 2017 |
| Intel Core i7-7740X | 4 / 8 | 4.3 / 4.5 GHz | 112 W | Jun 2017 |
| Intel Core i7-7800X | 6 / 12 | 3.5 / 4.0 GHz | 140 W | Jun 2017 |
| Intel Core i7-7820X | 8 / 16 | 3.6 / 4.5 GHz | 140 W | Jun 2017 |
| Intel Core i9-7900X | 10 / 20 | 3.3 / 4.5 GHz | 140 W | Jun 2017 |
| Intel Xeon W-2140B | 8 / 16 | 3.2 / 4.5 GHz | 105 W | 2017 |
| Intel Xeon W-2150B | 10 / 20 | 3.0 / 4.5 GHz | 125 W | 2017 |
| Intel Xeon W-2155 | 10 / 20 | 3.3 / 4.5 GHz | 140 W | 2017 |
| Intel Xeon W-2170B | 14 / 28 | 2.5 / 4.3 GHz | 140 W | 2017 |
| Intel Xeon W-2191B | 18 / 36 | 2.3 / 4.3 GHz | 140 W | 2017 |
Frequently asked questions
Which processors fit LGA 2066?
LGA 2066 takes Core X processors on X299 and Xeon W workstation parts on C422. The generations are Kaby Lake-X, Skylake-X, Cascade Lake-X, Skylake-W and Cascade Lake-W. Note that most X299 boards dropped Kaby Lake-X when they added Cascade Lake-X microcode.
Does Cascade Lake-X need a BIOS update on X299?
On early X299 boards, yes. Cascade Lake-X arrived in 2019 on boards from 2017, so boards like the ASUS WS X299 SAGE need BIOS 2002 or later. Newer X299 boards shipped with support. Check the board maker CPU support list for the minimum BIOS.
Do LGA 2011 coolers fit LGA 2066?
In most cases yes. Desktop LGA 2066 uses Square ILM with an 80 × 80 mm pattern, the same as LGA 2011, and makers list shared LGA 2011 and 2066 brackets. Boards with Narrow ILM need a Narrow bracket instead, so check the board before ordering.
What memory does LGA 2066 use?
Core X parts use quad channel DDR4. Early generations run DDR4-2400 to DDR4-2666 depending on model, and Cascade Lake-X runs DDR4-2933. Cascade Lake-X supports up to 256 GB. ECC is not supported on X299 with Core X.
What replaced LGA 2066?
LGA 2066 is legacy. Workstation and server designs moved to LGA 4189, and the mainstream desktop moved through later sockets. X299 remains a used market platform for high lane counts and quad channel memory.
Sources and verification
- LGA 2066 on Wikipedia
- Intel X299 Chipset specifications (Intel)
- Intel Core i9-10900X specifications (Intel)
- WS X299 SAGE CPU support list (ASUS)
- Dynatron R16 cooler, LGA 2066 square 80mm mounting (Dynatron)
- Noctua NH-D9DX i4 3U specifications, LGA 2066 Square and Narrow ILM (Noctua)
Facts last checked against these sources on . Page last edited on .