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Intel Core i9-9940X X-series

Intel Core i9-9940X X-Series: A Guide to an Outdated but Relevant Monster (2025)

April 2025. Updated to reflect the current market.

1. Key Specifications: Architecture, Process Technology, and Performance

Architecture and Process Technology

The Intel Core i9-9940X processor, released in 2018, is based on the Skylake-X microarchitecture and is manufactured using a 14nm process. By 2025, this is considered outdated, as modern Intel and AMD chips use 5–7nm processes. However, at its time, 14nm allowed for a balance between performance and thermal output.

Cores, Threads, and Clock Speeds

- 14 cores / 28 threads — ideal for multi-threaded tasks.

- Base clock: 3.3 GHz, turbo boost maximum: 4.5 GHz.

- L3 cache: 19.25 MB — sufficient for handling complex workloads.

Performance

- Geekbench 6: Single-Core — 1432, Multi-Core — 6701.

- For comparison, the Ryzen 9 5950X (16 cores) scores around ~1600/11500 (Single/Multi).

- In single-threaded tasks, it falls short compared to modern CPUs, but its multi-threaded performance remains competitive.

Key Features

- Support for Intel Turbo Boost Max 3.0 for automatic overclocking.

- Hyper-Threading technology for optimized multitasking.

- Unlocked multiplier — potential for overclocking.

2. Compatible Motherboards

Socket and Chipsets

- LGA 2066 socket — outdated, but still available in the secondary market.

- Chipsets: X299 (recommended), and also less functional C422 and others.

Selection Tips

- X299 motherboards (ASUS ROG Rampage VI Extreme, MSI X299 Gaming Pro Carbon) support:

- Quad-channel DDR4 memory.

- Numerous PCIe 3.0 lanes (up to 44) — relevant for workstations with multiple GPUs/NVMe drives.

- New motherboard prices (2025): starting from $250 (basic models) to $400+ (high-end).

- Advice: Look for models with enhanced VRMs (e.g., 8+ phases) for stable overclocking.

3. Supported Memory

Types and Configurations

- DDR4 supporting up to 256 GB (8 slots × 32 GB).

- Frequencies: up to 2666 MHz (without overclocking), but many boards allow overclocking to 3600+ MHz.

- Quad-channel mode — an advantage over consumer platforms (e.g., AM4).

2025 Recommendations

- Optimal choice: 4 × 16 GB DDR4-3200 (64 GB) — a balance of price and performance.

- DDR5 is not supported — this is the main drawback for modern tasks that require high bandwidth.

4. Power Supplies: Calculation for TDP 165W

Basic Requirements

- Nominal TDP — 165W, but under overclocking, consumption can reach 250–300W.

- Minimum power supply wattage: 750W (considering a powerful graphics card, such as RTX 4080).

- Recommended standards: 80+ Gold or Platinum (efficiency ≥90%).

Power Supply Examples

- Corsair RM850x (2025): $140 — quiet, reliable, 10-year warranty.

- Be Quiet! Straight Power 11 1000W: $180 — headroom for upgrades.

Important! Do not skimp on the power supply — the high energy consumption of the CPU and GPU requires stable voltage.

5. Pros and Cons

Pros

- Multi-threaded power — rendering, encoding, 3D modeling.

- Compatibility with X299 — upgrade for older workstations.

- Overclocking — potential for enthusiasts.

Cons

- High energy consumption — 165W compared to 105W for Ryzen 9 7900X.

- Outdated process technology — cooling requirements necessitate powerful solutions.

- No PCIe 4.0/5.0 support — a limitation for high-speed NVMe and modern GPUs.

6. Use Cases

Work Tasks

- 3D Rendering (Blender, V-Ray): 14 cores perform faster than 8-core CPUs from 2023-2024.

- Video Editing (Premiere Pro): Rendering 4K projects with effects — 28 threads will reduce processing time.

- Virtualization: Running multiple VMs without lag.

Gaming

- Average performance in 2025: In Full HD with RTX 4070 — 90–120 FPS (Cyberpunk 2077, Ultra).

- Weaknesses: Lower IPC (instructions per cycle) compared to Ryzen 7000/8000 — drops in CPU-bound scenes.

Multimedia

- Streaming (OBS + gaming) — 28 threads easily handle x264 encoding.

7. Comparison with Competitors

AMD Ryzen 9 5950X (2020)

- 16 cores / 32 threads, 7nm, TDP 105W.

- Geekbench 6: ~1600/11500.

- Pros: Energy efficiency, PCIe 4.0 support.

- Price (2025): $350 (new) — the best price-to-performance ratio.

Intel Core i9-13900K (2022)

- 24 cores (8P + 16E), 10nm, TDP 125W.

- Geekbench 6: ~2200/22000.

- Pros: Leader in single-threaded tasks.

Conclusion: The i9-9940X falls behind in energy efficiency and IPC, but outperforms budget newcomers in multi-threaded applications.

8. Practical Building Tips

Cooling

- Minimum: 240mm AIO (e.g., NZXT Kraken X63).

- Optimal: 360mm AIO or custom water cooling.

Motherboard

- Choose models with VRM heatsinks (ASUS Prime X299-A II).

Memory

- 4 × 16 GB DDR4-3200 — activating quad-channel mode.

Additional

- Use NVMe SSDs (PCIe 3.0) to reduce bottlenecks.

9. Final Verdict: Who is the i9-9940X Suitable for in 2025?

Who It's For:

- Owners of X299 platforms wanting to upgrade without replacing the motherboard.

- Budget workstations: Buying a used CPU for $200–250 + a new X299 motherboard ($300) is cheaper than switching to AM5/LGA 1700.

- Overclocking enthusiasts: Experimenting with overclocking on "old hardware."

Why You Might Not Want It:

- No support for DDR5 and PCIe 5.0.

- High energy consumption.

Alternative: Ryzen 9 7900X ($450) or Intel Core i7-14700K ($400) — better IPC, PCIe 5.0, DDR5.

Final Verdict: The Intel Core i9-9940X is a niche solution for specific tasks. In 2025, it remains relevant only in the hands of those who value multi-core performance and are not ready to invest in a new platform.

Basic

Label Name

Intel

Platform

Desktop

Launch Date

October 2018

Model Name

The Intel processor number is just one of several factors - along with processor brand, system configurations, and system-level benchmarks - to be considered when choosing the right processor for your computing needs.

i9-9940X

Code Name

SkyLake

CPU Specifications

Total Cores

Cores is a hardware term that describes the number of independent central processing units in a single computing component (die or chip).

Total Threads

Where applicable, Intel® Hyper-Threading Technology is only available on Performance-cores.

Basic Frequency

3.30 GHz

Max Turbo Frequency

Max Turbo Frequency is the maximum single-core frequency at which the processor is capable of operating using Intel® Turbo Boost Technology and, if present, Intel® Turbo Boost Max Technology 3.0 and Intel® Thermal Velocity Boost. Frequency is typically measured in gigahertz (GHz), or billion cycles per second.

4.40 GHz

Intel Turbo Boost Max Technology 3.0 Frequency

Intel® Turbo Boost Max Technology 3.0 identifies the best performing core(s) on a processor and provides increased performance on those cores through increasing frequency as needed by taking advantage of power and thermal headroom. Intel® Turbo Boost Max Technology 3.0 frequency is the clock frequency of the CPU when running in this mode.

4.50 GHz

Intel Turbo Boost Max Technology 3.0

Yes

Intel Hyper-Threading Technology

Intel® Hyper-Threading Technology (Intel® HT Technology) delivers two processing threads per physical core. Highly threaded applications can get more work done in parallel, completing tasks sooner.

Yes

Intel Turbo Boost Technology

Intel® Turbo Boost Technology dynamically increases the processor's frequency as needed by taking advantage of thermal and power headroom to give you a burst of speed when you need it, and increased energy efficiency when you don’t.

2.0

CPU Socket

The socket is the component that provides the mechanical and electrical connections between the processor and motherboard.

FCLGA2066

Technology

Lithography refers to the semiconductor technology used to manufacture an integrated circuit, and is reported in nanometer (nm), indicative of the size of features built on the semiconductor.

14 nm

TDP

165 W

Max. Operating Temperature

Junction Temperature is the maximum temperature allowed at the processor die.

88°C

PCI Express Version

PCI Express Revision is the supported version of the PCI Express standard. Peripheral Component Interconnect Express (or PCIe) is a high-speed serial computer expansion bus standard for attaching hardware devices to a computer. The different PCI Express versions support different data rates.

3.0

Number of PCI Express Lanes

A PCI Express (PCIe) lane consists of two differential signaling pairs, one for receiving data, one for transmitting data, and is the basic unit of the PCIe bus. Max # of PCI Express Lanes is the total number of supported lanes.

Intel 64

Intel® 64 architecture delivers 64-bit computing on server, workstation, desktop and mobile platforms when combined with supporting software.¹ Intel 64 architecture improves performance by allowing systems to address more than 4 GB of both virtual and physical memory.

Yes

Memory Specifications

Memory Type

Intel® processors come in four different types: Single Channel, Dual Channel, Triple Channel, and Flex Mode. Maximum supported memory speed may be lower when populating multiple DIMMs per channel on products that support multiple memory channels.

DDR4-2666

Max Memory Size

Max memory size refers to the maximum memory capacity supported by the processor.

128 GB

Memory Channels

The number of memory channels refers to the bandwidth operation for real world application.

Bus Speed

8 GT/s

Max Memory Bandwidth

Max Memory bandwidth is the maximum rate at which data can be read from or stored into a semiconductor memory by the processor (in GB/s).

85 GB/s

ECC Memory Supported

ECC Memory Supported indicates processor support for Error-Correcting Code memory. ECC memory is a type of system memory that can detect and correct common kinds of internal data corruption. Note that ECC memory support requires both processor and chipset support.

Miscellaneous

Intel Virtualization Technology for Directed I/O (VT-d)

Intel® Virtualization Technology for Directed I/O (VT-d) continues from the existing support for IA-32 (VT-x) and Itanium® processor (VT-i) virtualization adding new support for I/O-device virtualization. Intel VT-d can help end users improve security and reliability of the systems and also improve performance of I/O devices in virtualized environments.

Yes

Intel Virtualization Technology (VT-x)

Intel® Virtualization Technology (VT-x) allows one hardware platform to function as multiple “virtual” platforms. It offers improved manageability by limiting downtime and maintaining productivity by isolating computing activities into separate partitions.

Yes

Intel Standard Manageability (ISM)

Intel® Standard Manageability is the manageability solution for Intel vPro® Essentials platforms and is a subset of Intel® AMT with out-of-band management over Ethernet and Wi-Fi, but no KVM or new life cycle management features.

Intel® SSE4.1 | Intel® SSE4.2 | Intel® AVX2 | Intel® AVX-512

Number of AVX-512 FMA Units

Enhanced Intel SpeedStep Technology

Enhanced Intel SpeedStep® Technology is an advanced means of enabling high performance while meeting the power-conservation needs of mobile systems. Conventional Intel SpeedStep® Technology switches both voltage and frequency in tandem between high and low levels in response to processor load. Enhanced Intel SpeedStep® Technology builds upon that architecture using design strategies such as Separation between Voltage and Frequency Changes, and Clock Partitioning and Recovery.

Yes

Execute Disable Bit

Execute Disable Bit is a hardware-based security feature that can reduce exposure to viruses and malicious-code attacks and prevent harmful software from executing and propagating on the server or network.

Yes

Cache

CPU Cache is an area of fast memory located on the processor. Intel® Smart Cache refers to the architecture that allows all cores to dynamically share access to the last level cache.

19.25 MB Intel® Smart Cache

Intel AES New Instructions

Intel® AES New Instructions (Intel® AES-NI) are a set of instructions that enable fast and secure data encryption and decryption. AES-NI are valuable for a wide range of cryptographic applications, for example: applications that perform bulk encryption/decryption, authentication, random number generation, and authenticated encryption.

Yes

Benchmarks

Geekbench 6

Single Core Score

1432

Geekbench 6

Multi Core Score

6701

Geekbench 5

Single Core Score

1121

Geekbench 5

Multi Core Score

12067

Compared to Other CPU

Geekbench 6 Single Core

Xeon W-10885M

1542 +7.7%

Core i7-8665U

1484 +3.6%

Core i9-9940X X-series

1432

Xeon W-2145

1384 -3.4%

Xeon W-2170B

1350 -5.7%

Geekbench 6 Multi Core

Core i9-11900H

7563 +12.9%

Ryzen 9 5900HS

7123 +6.3%

Core i9-9940X X-series

6701

Xeon E-2176G

6330 -5.5%

Ryzen 7 4800H

5883 -12.2%

Geekbench 5 Single Core

Core i3-1115G4

1183 +5.5%

Core i7-1180G7

1154 +2.9%

Core i9-9940X X-series

1121

Core i7-8700B

1107 -1.2%

Ryzen 7 PRO 4750U

1084 -3.3%

Geekbench 5 Multi Core

Core i7-12700KF

14537 +20.5%

Core i9-13905H

13046 +8.1%

Core i9-9940X X-series

12067

Ryzen Threadripper 1950X

10995 -8.9%

Core i9-7920X X-series

10169 -15.7%