i5-8400B vs i7-3940XM
Primary details
Comparing Core i7-3940XM and Core i5-8400B processor market type (desktop or notebook), architecture, sales start time and price.
| Place in the ranking | 1482 | not rated |
| Place by popularity | not in top-100 | not in top-100 |
| Market segment | Laptop | Laptop |
| Series | Intel Core i7 | Intel Core i5 |
| Power efficiency | 6.33 | no data |
| Architecture codename | Ivy Bridge (2012−2013) | Coffee Lake (2017−2019) |
| Release date | 3 September 2012 (12 years ago) | 2 April 2018 (6 years ago) |
| Launch price (MSRP) | $1,096 | $182 |
Detailed specifications
Core i7-3940XM and Core i5-8400B 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 | 4 (Quad-Core) | 6 (Hexa-Core) |
| Threads | 8 | 6 |
| Base clock speed | 3 GHz | 2.8 GHz |
| Boost clock speed | 3.9 GHz | 4 GHz |
| Bus type | no data | DMI 3.0 |
| Bus rate | 5 GT/s | 4 × 8 GT/s |
| Multiplier | no data | 28 |
| L1 cache | 64K (per core) | 384 KB |
| L2 cache | 256K (per core) | 1.5 MB |
| L3 cache | 8 MB (shared) | 9 MB |
| Chip lithography | 22 nm | 14 nm |
| Die size | 160 mm2 | 126 mm2 |
| Maximum core temperature | 105 °C | 100 °C |
| Number of transistors | 1,400 million | no data |
| 64 bit support | + | + |
| Windows 11 compatibility | - | + |
| Unlocked multiplier | + | - |
Compatibility
Information on Core i7-3940XM and Core i5-8400B 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 | 1 (Uniprocessor) |
| Socket | FCPGA988 | FCBGA1440 |
| Power consumption (TDP) | 55 Watt | 65 Watt |
Technologies and extensions
Technological solutions and additional instructions supported by Core i7-3940XM and Core i5-8400B. You'll probably need this information if you require some particular technology.
| Instruction set extensions | Intel® AVX | Intel® SSE4.1, Intel® SSE4.2, Intel® AVX2 |
| AES-NI | + | + |
| AVX | + | + |
| Enhanced SpeedStep (EIST) | + | + |
| My WiFi | + | no data |
| Turbo Boost Technology | 2.0 | 2.0 |
| Hyper-Threading Technology | + | - |
| Idle States | + | + |
| Thermal Monitoring | + | + |
| Flex Memory Access | + | no data |
| Demand Based Switching | - | no data |
| FDI | + | no data |
| Fast Memory Access | + | no data |
Security technologies
Core i7-3940XM and Core i5-8400B technologies aimed at improving security, for example, by protecting against hacks.
| TXT | + | - |
| EDB | + | + |
| Secure Key | no data | + |
| MPX | - | + |
| Identity Protection | + | + |
| SGX | no data | Yes with Intel® ME |
| OS Guard | no data | + |
| Anti-Theft | + | no data |
Virtualization technologies
Virtual machine speed-up technologies supported by Core i7-3940XM and Core i5-8400B are enumerated here.
| AMD-V | + | - |
| VT-d | + | + |
| VT-x | + | + |
| EPT | + | + |
Memory specs
Types, maximum amount and channel quantity of RAM supported by Core i7-3940XM and Core i5-8400B. Depending on the motherboard, higher memory frequencies may be supported.
| Supported memory types | DDR3 | DDR4-2666 |
| Maximum memory size | 32 GB | 64 GB |
| Max memory channels | 2 | 2 |
| Maximum memory bandwidth | 25.6 GB/s | 42.671 GB/s |
Graphics specifications
General parameters of integrated GPUs, if any.
| Integrated graphics card Compare | Intel HD Graphics 4000 | Intel UHD Graphics 630 |
| Max video memory | no data | 64 GB |
| Quick Sync Video | + | + |
| Clear Video | no data | + |
| Clear Video HD | + | + |
| Graphics max frequency | 1.35 GHz | 1.05 GHz |
| InTru 3D | + | + |
Graphics interfaces
Available interfaces and connections of Core i7-3940XM and Core i5-8400B integrated GPUs.
| Number of displays supported | 3 | 3 |
| eDP | + | no data |
| DisplayPort | + | - |
| HDMI | + | - |
| SDVO | + | no data |
| CRT | + | no data |
Graphics image quality
Maximum display resolutions supported by Core i7-3940XM and Core i5-8400B integrated GPUs, including resolutions over different interfaces.
| 4K resolution support | no data | + |
| Max resolution over HDMI 1.4 | no data | 4096x2304@30Hz |
| Max resolution over eDP | no data | 4096x2304@60Hz |
| Max resolution over DisplayPort | no data | 4096x2304@60Hz |
Graphics API support
APIs supported by Core i7-3940XM and Core i5-8400B 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 i7-3940XM and Core i5-8400B.
| PCIe version | 3.0 | 3.0 |
| PCI Express lanes | 16 | 16 |
Pros & cons summary
| Integrated graphics card | 1.18 | 3.09 |
| Recency | 3 September 2012 | 2 April 2018 |
| Physical cores | 4 | 6 |
| Threads | 8 | 6 |
| Chip lithography | 22 nm | 14 nm |
| Power consumption (TDP) | 55 Watt | 65 Watt |
i7-3940XM has 33.3% more threads, and 18.2% lower power consumption.
i5-8400B, on the other hand, has 161.9% faster integrated GPU, an age advantage of 5 years, 50% more physical cores, and a 57.1% more advanced lithography process.
We couldn't decide between Core i7-3940XM and Core i5-8400B. We've got no test results to judge.
Should you still have questions on choice between Core i7-3940XM and Core i5-8400B, ask them in Comments section, and we shall answer.
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