i7-8700K vs i9-7940X
Aggregate performance score
Core i9-7940X outperforms Core i7-8700K by an impressive 90% based on our aggregate benchmark results.
Primary details
Comparing Core i9-7940X and Core i7-8700K processor market type (desktop or notebook), architecture, sales start time and price.
| Place in the ranking | 398 | 869 |
| Place by popularity | not in top-100 | not in top-100 |
| Cost-effectiveness evaluation | 3.16 | 4.83 |
| Market segment | Desktop processor | Desktop processor |
| Series | Intel Core i9 | Intel Core i7 |
| Power efficiency | 9.37 | 8.54 |
| Architecture codename | Skylake (server) (2017−2019) | Coffee Lake-S (2017−2018) |
| Release date | 30 May 2017 (7 years ago) | 5 October 2017 (7 years ago) |
| Launch price (MSRP) | $1,399 | $359 |
Cost-effectiveness evaluation
Performance per price, higher is better.
i7-8700K has 53% better value for money than i9-7940X.
Detailed specifications
Core i9-7940X and Core i7-8700K basic parameters such as number of cores, number of threads, base frequency and turbo boost clock, lithography, cache size and multiplier lock state. These parameters indirectly say of CPU speed, though for more precise assessment you have to consider their test results.
| Physical cores | 14 (Tetradeca-Core) | 6 (Hexa-Core) |
| Threads | 28 | 12 |
| Base clock speed | 3.1 GHz | 3.7 GHz |
| Boost clock speed | 4.4 GHz | 4.7 GHz |
| Bus type | DMI 3.0 | DMI 3.0 |
| Bus rate | 4 × 8 GT/s | 4 × 8 GT/s |
| Multiplier | no data | 37 |
| L1 cache | 896 KB | 64K (per core) |
| L2 cache | 14 MB | 256K (per core) |
| L3 cache | 19.25 MB (shared) | 12288 KB |
| Chip lithography | 14 nm | 14 nm |
| Die size | 484 mm2 | 149 mm2 |
| Maximum core temperature | 102 °C | 100 °C |
| Maximum case temperature (TCase) | no data | 72 °C |
| 64 bit support | + | + |
| Windows 11 compatibility | + | + |
| Unlocked multiplier | + | + |
Compatibility
Information on Core i9-7940X and Core i7-8700K compatibility with other computer components: motherboard (look for socket type), power supply unit (look for power consumption) etc. Useful when planning a future computer configuration or upgrading an existing one. Note that power consumption of some processors can well exceed their nominal TDP, even without overclocking. Some can even double their declared thermals given that the motherboard allows to tune the CPU power parameters.
| Number of CPUs in a configuration | 1 (Uniprocessor) | 1 (Uniprocessor) |
| Socket | FCLGA2066 | FCLGA1151 |
| Power consumption (TDP) | 165 Watt | 95 Watt |
Technologies and extensions
Technological solutions and additional instructions supported by Core i9-7940X and Core i7-8700K. You'll probably need this information if you require some particular technology.
| Instruction set extensions | Intel® SSE4.1, Intel® SSE4.2, Intel® AVX2, Intel® AVX-512 | Intel® SSE4.1, Intel® SSE4.2, Intel® AVX2 |
| AES-NI | + | + |
| AVX | + | + |
| vPro | no data | + |
| Enhanced SpeedStep (EIST) | + | + |
| Turbo Boost Technology | 2.0 | 2.0 |
| Hyper-Threading Technology | + | + |
| TSX | + | + |
| Idle States | no data | + |
| Thermal Monitoring | - | + |
| SIPP | - | + |
| Turbo Boost Max 3.0 | + | no data |
Security technologies
Core i9-7940X and Core i7-8700K technologies aimed at improving security, for example, by protecting against hacks.
| TXT | no data | + |
| EDB | + | + |
| Secure Key | no data | + |
| MPX | - | + |
| Identity Protection | - | + |
| SGX | no data | Yes with Intel® ME |
| OS Guard | no data | + |
Virtualization technologies
Virtual machine speed-up technologies supported by Core i9-7940X and Core i7-8700K are enumerated here.
| AMD-V | - | + |
| VT-d | + | + |
| VT-x | + | + |
| EPT | no data | + |
Memory specs
Types, maximum amount and channel quantity of RAM supported by Core i9-7940X and Core i7-8700K. Depending on the motherboard, higher memory frequencies may be supported.
| Supported memory types | DDR4-2666 | DDR3, DDR4 |
| Maximum memory size | 128 GB | 128 GB |
| Max memory channels | 4 | 2 |
| Maximum memory bandwidth | 85.33 GB/s | 42.671 GB/s |
Graphics specifications
General parameters of integrated GPUs, if any.
| Integrated graphics card | N/A | Intel UHD Graphics 630 |
| Max video memory | no data | 64 GB |
| Quick Sync Video | - | + |
| Clear Video | no data | + |
| Clear Video HD | no data | + |
| Graphics max frequency | no data | 1.2 GHz |
| InTru 3D | no data | + |
Graphics interfaces
Available interfaces and connections of Core i9-7940X and Core i7-8700K integrated GPUs.
| Number of displays supported | no data | 3 |
Graphics image quality
Maximum display resolutions supported by Core i9-7940X and Core i7-8700K integrated GPUs, including resolutions over different interfaces.
| 4K resolution support | no data | + |
| Max resolution over HDMI 1.4 | no data | 4096 x 2304@24Hz |
| Max resolution over eDP | no data | 4096 x 2304@60Hz |
| Max resolution over DisplayPort | no data | 4096 x 2304@60Hz |
Graphics API support
APIs supported by Core i9-7940X and Core i7-8700K integrated GPUs, sometimes API versions are included.
| DirectX | no data | 12 |
| OpenGL | no data | 4.5 |
Peripherals
Specifications and connection of peripherals supported by Core i9-7940X and Core i7-8700K.
| PCIe version | 3.0 | 3.0 |
| PCI Express lanes | 44 | 16 |
Synthetic benchmark performance
Various benchmark results of the processors in comparison. Overall score is measured in points in 0-100 range, higher is better.
Combined synthetic benchmark score
This is our combined benchmark performance rating. We are regularly improving our combining algorithms, but if you find some perceived inconsistencies, feel free to speak up in comments section, we usually fix problems quickly.
Passmark
Passmark CPU Mark is a widespread benchmark, consisting of 8 different types of workload, including integer and floating point math, extended instructions, compression, encryption and physics calculation. There is also one separate single-threaded scenario measuring single-core performance.
GeekBench 5 Single-Core
GeekBench 5 Single-Core is a cross-platform application developed in the form of CPU tests that independently recreate certain real-world tasks with which to accurately measure performance. This version uses only a single CPU core.
GeekBench 5 Multi-Core
GeekBench 5 Multi-Core is a cross-platform application developed in the form of CPU tests that independently recreate certain real-world tasks with which to accurately measure performance. This version uses all available CPU cores.
Pros & cons summary
| Performance score | 16.95 | 8.90 |
| Recency | 30 May 2017 | 5 October 2017 |
| Physical cores | 14 | 6 |
| Threads | 28 | 12 |
| Power consumption (TDP) | 165 Watt | 95 Watt |
i9-7940X has a 90.4% higher aggregate performance score, and 133.3% more physical cores and 133.3% more threads.
i7-8700K, on the other hand, has an age advantage of 4 months, and 73.7% lower power consumption.
The Core i9-7940X is our recommended choice as it beats the Core i7-8700K in performance tests.
Should you still have questions on choice between Core i9-7940X and Core i7-8700K, ask them in Comments section, and we shall answer.
Similar processor comparisons
We picked several similar comparisons of processors in the same market segment and performance relatively close to those reviewed on this page.
