i7-1255U vs i5-6400T
Aggregate performance score
Core i7-1255U outperforms Core i5-6400T by a whopping 216% based on our aggregate benchmark results.
Primary details
Comparing Core i5-6400T and Core i7-1255U processor market type (desktop or notebook), architecture, sales start time and price.
| Place in the ranking | 1712 | 895 |
| Place by popularity | not in top-100 | 78 |
| Cost-effectiveness evaluation | 0.47 | no data |
| Market segment | Desktop processor | Laptop |
| Series | Intel Core i5 (Desktop) | Intel Alder Lake-M |
| Power efficiency | 7.30 | 53.88 |
| Architecture codename | Skylake (2015−2016) | Alder Lake-U (2022) |
| Release date | 1 September 2015 (9 years ago) | 23 February 2022 (2 years ago) |
| Launch price (MSRP) | $192 | no data |
Cost-effectiveness evaluation
Performance per price, higher is better.
Detailed specifications
Core i5-6400T and Core i7-1255U 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) | 10 (Deca-Core) |
| Threads | 4 | 12 |
| Base clock speed | 2.2 GHz | 1.7 GHz |
| Boost clock speed | 2.8 GHz | 4.7 GHz |
| Bus type | DMI 3.0 | no data |
| Bus rate | 4 × 8 GT/s | no data |
| Multiplier | 22 | no data |
| L1 cache | 256 KB | 80K (per core) |
| L2 cache | 1 MB | 1.25 MB (per core) |
| L3 cache | 6 MB | 12 MB (shared) |
| Chip lithography | 14 nm | Intel 7 nm |
| Die size | 122 mm2 | no data |
| Maximum core temperature | 66 °C | 100 °C |
| 64 bit support | + | + |
| Windows 11 compatibility | - | + |
Compatibility
Information on Core i5-6400T and Core i7-1255U 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 |
| Socket | FCLGA1151 | FCBGA1744 |
| Power consumption (TDP) | 35 Watt | 15 Watt |
Technologies and extensions
Technological solutions and additional instructions supported by Core i5-6400T and Core i7-1255U. You'll probably need this information if you require some particular technology.
| Instruction set extensions | Intel® SSE4.1, Intel® SSE4.2, Intel® AVX2 | Intel® SSE4.1, Intel® SSE4.2, Intel® AVX2 |
| AES-NI | + | + |
| FMA | - | + |
| AVX | + | + |
| vPro | + | no data |
| Enhanced SpeedStep (EIST) | + | + |
| Speed Shift | no data | + |
| Turbo Boost Technology | 2.0 | no data |
| Hyper-Threading Technology | - | + |
| TSX | - | + |
| Idle States | + | no data |
| Thermal Monitoring | + | + |
| Flex Memory Access | no data | + |
| Deep Learning Boost | - | + |
Security technologies
Core i5-6400T and Core i7-1255U technologies aimed at improving security, for example, by protecting against hacks.
| TXT | - | + |
| EDB | + | + |
| Secure Key | + | + |
| MPX | + | - |
| Identity Protection | + | - |
| SGX | Yes with Intel® ME | no data |
| OS Guard | + | + |
Virtualization technologies
Virtual machine speed-up technologies supported by Core i5-6400T and Core i7-1255U are enumerated here.
| AMD-V | + | - |
| VT-d | + | + |
| VT-x | + | + |
| EPT | + | + |
Memory specs
Types, maximum amount and channel quantity of RAM supported by Core i5-6400T and Core i7-1255U. Depending on the motherboard, higher memory frequencies may be supported.
| Supported memory types | DDR3, DDR4 | DDR4, DDR5 |
| Maximum memory size | 64 GB | 64 GB |
| Max memory channels | 2 | 2 |
| Maximum memory bandwidth | 34.134 GB/s | no data |
Graphics specifications
General parameters of integrated GPUs, if any.
| Integrated graphics card | Intel HD Graphics 530 | Intel® Iris® Xe Graphics eligible |
| Max video memory | 64 GB | no data |
| Quick Sync Video | + | + |
| Clear Video | + | no data |
| Clear Video HD | + | no data |
| Graphics max frequency | 950 MHz | 1.25 GHz |
| Execution Units | no data | 96 |
| InTru 3D | + | no data |
Graphics interfaces
Available interfaces and connections of Core i5-6400T and Core i7-1255U integrated GPUs.
| Number of displays supported | 3 | 4 |
| eDP | + | no data |
| DisplayPort | + | - |
| HDMI | + | - |
| DVI | + | no data |
Graphics image quality
Maximum display resolutions supported by Core i5-6400T and Core i7-1255U integrated GPUs, including resolutions over different interfaces.
| 4K resolution support | + | no data |
| Max resolution over HDMI 1.4 | 4096x2304@24Hz | 4096 x 2304 @ 60Hz |
| Max resolution over eDP | 4096x2304@60Hz | 4096 x 2304 @ 120Hz |
| Max resolution over DisplayPort | 4096x2304@60Hz | 7680 x 4320 @ 60Hz |
| Max resolution over VGA | N/A | no data |
Graphics API support
APIs supported by Core i5-6400T and Core i7-1255U integrated GPUs, sometimes API versions are included.
| DirectX | 12 | 12.1 |
| OpenGL | 4.5 | 4.6 |
Peripherals
Specifications and connection of peripherals supported by Core i5-6400T and Core i7-1255U.
| PCIe version | 3.0 | 4.0 |
| PCI Express lanes | 16 | 20 |
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.
Cinebench 15 64-bit multi-core
Cinebench Release 15 Multi Core is a variant of Cinebench R15 which uses all the processor threads.
Cinebench 15 64-bit single-core
Cinebench R15 (standing for Release 15) is a benchmark made by Maxon, authors of Cinema 4D. It was superseded by later versions of Cinebench, which use more modern variants of Cinema 4D engine. The Single Core version (sometimes called Single-Thread) only uses a single processor thread to render a room full of reflective spheres and light sources.
Pros & cons summary
| Performance score | 2.70 | 8.54 |
| Recency | 1 September 2015 | 23 February 2022 |
| Physical cores | 4 | 10 |
| Threads | 4 | 12 |
| Power consumption (TDP) | 35 Watt | 15 Watt |
i7-1255U has a 216.3% higher aggregate performance score, an age advantage of 6 years, 150% more physical cores and 200% more threads, and 133.3% lower power consumption.
The Core i7-1255U is our recommended choice as it beats the Core i5-6400T in performance tests.
Note that Core i5-6400T is a desktop processor while Core i7-1255U is a notebook one.
Should you still have questions on choice between Core i5-6400T and Core i7-1255U, ask them in Comments section, and we shall answer.
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