This article covers インテル ( intel) Corei9-7940X Processor 3.10-4.40GHz， 19.25MB， 14C.

Overview

The Intel Core i9-7940X is a high-end desktop processor from the Skylake-X family, launched in 2017. With 14 cores and 28 threads, a base clock of 3.10 GHz and a max turbo of 4.30 GHz, it still offers strong multi-threaded performance that can rival many modern mid-range CPUs. The 19.25 MB L3 cache and 165W TDP place it firmly in the enthusiast HEDT segment, ideal for creative workloads and virtualization.
Built for the LGA2066 socket and Intel X299 chipset, the i9-7940X provides 44 PCIe 3.0 lanes and quad-channel DDR4 memory support, giving you exceptional expansion capability. However, it is not compatible with modern mainstream platforms (LGA1700/LGA1851 or AM5), so you will need a dedicated X299 motherboard. Memory is limited to DDR4 (up to 2666 MHz officially), but high-capacity DIMMs allow up to 128 GB.
Today, the i9-7940X can still be found through online retailers and the used market at a significantly reduced price compared to its original $1,399 MSRP. For budget-conscious users who need many cores and threads, it can be a compelling option—provided you are willing to accept its higher power draw and older platform limitations.

Compatibility Guide

The Core i9-7940X uses the LGA2066 socket and requires an Intel X299 chipset motherboard. These boards typically come in ATX or E-ATX form factors and feature quad-channel DDR4 memory slots. Official memory speed support is DDR4-2666, though many X299 boards support higher speeds via XMP profiles. Always check the motherboard's QVL list before purchasing RAM.
Storage connectivity depends on the motherboard, but X299 chipsets generally include multiple SATA 6Gbps ports and several M.2 NVMe slots. With 44 CPU-direct PCIe 3.0 lanes, you can run multiple GPUs and NVMe SSDs without bandwidth concerns. However, PCIe 3.0 means you won't get the full speed of PCIe 4.0/5.0 storage devices.
Power requirements: the CPU alone has a 165W TDP, but real-world load can approach 200W. For a system with a mid-range to high-end GPU (e.g., GeForce RTX 4070), a 750W-850W power supply is recommended. The CPU cooler should be at least a 120mm tower air cooler or a 240mm AIO liquid cooler to handle sustained loads.

Product Info

Released in September 2017 at an MSRP of $1,399, the Core i9-7940X can now be found for around ¥57,000 JPY on Japanese retailers (e.g., online retailers, as of September 2026). The retail box version includes a 3-year Intel warranty Availability is limited to remaining stock and the used market.
In the current market, the i9-7940X sits in the 'high-end desktop' (HEDT) category. Its 14 cores are still respectable compared to modern Core i5/i7 chips, but its IPC and power efficiency lag significantly behind newer architectures. It is best suited for users who prioritize raw multi-threaded throughput over single-thread performance or modern features.

Best Use Cases

  • Content creators doing video editing and 3D rendering: The 14 cores/28 threads excel in multi-threaded applications like Adobe Premiere Pro (software encoding), Blender Cycles, and Cinebench. If your workflow involves long render times, this CPU can offer great value for the price. Note that light, single-threaded editing may actually be faster on a newer CPU.
  • Developers running multiple VMs or containers: With 28 threads and 44 PCIe lanes, you can comfortably run several virtual machines or Docker containers simultaneously. Expandable storage and networking (via PCIe slots) make this a viable workstation on a budget. However, if you need more than 128 GB of RAM, you are out of luck—this platform tops out at 128 GB.
  • Enthusiasts who want high core count on a budget: The i9-7940X offers a great cores-per-dollar ratio compared to modern high-core CPUs like the Core i9-14900K. If you are willing to accept the older platform (limited motherboard availability, higher power consumption) and your work is I/O intensive but not frequency-sensitive, this could be a smart purchase.
  • Hobbyists building an HEDT system for fun: The LGA2066/X299 platform has a certain nostalgia factor and offers unique features like quad-channel memory and massive PCIe lane counts. If you enjoy tinkering with older hardware and don't mind potential compromises in everyday responsiveness, this CPU can be an interesting build project.

Things to Consider

First and foremost, the Core i9-7940X is an old platform. Single-thread performance is significantly behind modern CPUs—expect a 30-50% IPC deficit compared to Intel's 12th-14th Gen. For gaming, this means lower frame rates even with the same GPU, especially at 1080p. If gaming is your primary use, you are better off with a modern mid-range chip like the Core i5-14600K or Ryzen 5 7600.
Motherboard availability is a real concern. X299 boards are no longer produced, and finding a new one is difficult. Used boards may come with risks like degraded VRMs or BIOS issues. Al

Product Disclosure (Amazon)

  • Manufacturer: インテル
  • Seller: Reg shop
  • Fulfilled by: Reg shop
  • ASIN: B076KXLR6K
  • Note: This article covers a manufacturer-made product based on Amazon listing details.