i9-7900X vs Ultra 7 251HX
Aggregate performance score
Core Ultra 7 251HX outperforms Core i9-7900X by a whopping 126% based on our aggregate benchmark results.
Contents
Primary details
Comparing processor market type (desktop or notebook), architecture, sales start time and price.
| Place in the ranking | 263 | 824 |
| Place by popularity | not in top-100 | not in top-100 |
| Cost-effectiveness evaluation | no data | 1.31 |
| Market segment | Laptop | Desktop processor |
| Series | Intel Arrow Lake | Core i9 (Desktop) |
| Power efficiency | 7.11 | 3.59 |
| Designer | Intel | Intel |
| Manufacturer | no data | Intel |
| Architecture codename | Arrow Lake-HX (2025−2026) | Skylake (server) (2017−2018) |
| Release date | 1 April 2026 (less than a year ago) | 26 June 2017 (9 years ago) |
| Launch price (MSRP) | no data | $999 |
Cost-effectiveness evaluation
Performance per price, higher is better.
Performance to price scatter graph
Currently popular graphics cards are shown for comparison.
Detailed specifications
Basic parameters of Core Ultra 7 251HX and Core i9-7900X: 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 | 18 (Octadeca-Core) | 10 (Deca-Core) |
| Performance-cores | 6 | no data |
| Efficient-cores | 12 | no data |
| Threads | 18 | 20 |
| Base clock speed | 2.5 GHz | 3.3 GHz |
| Boost clock speed | 5.1 GHz | 4.5 GHz |
| Bus type | no data | DMI 3.0 |
| Bus rate | no data | 4 × 8 GT/s |
| Multiplier | no data | 33 |
| L1 cache | no data | 64 KB (per core) |
| L2 cache | 30 MB | 1 MB (per core) |
| L3 cache | 30 MB | 14 MB (shared) |
| Chip lithography | 3 nm | 14 nm |
| Maximum core temperature | no data | 95 °C |
| Maximum case temperature (TCase) | no data | 72 °C |
| 64 bit support | + | + |
| Windows 11 compatibility | no data | + |
| Unlocked multiplier | - | + |
Compatibility
Information on Core Ultra 7 251HX and Core i9-7900X 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 | no data | 1 (Uniprocessor) |
| Socket | FCBGA2114 | Socket R4 |
| Power consumption (TDP) | 160 Watt | 140 Watt |
Technologies and extensions
Technological solutions and additional instructions supported by Core Ultra 7 251HX and Core i9-7900X. 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, Intel® AVX-512 |
| AES-NI | + | + |
| AVX | - | + |
| vPro | no data | + |
| Enhanced SpeedStep (EIST) | + | + |
| Speed Shift | + | no data |
| Turbo Boost Technology | 2.0 | 2.0 |
| Hyper-Threading Technology | - | + |
| TSX | - | + |
| Idle States | + | no data |
| Thermal Monitoring | + | - |
| Turbo Boost Max 3.0 | - | + |
| Deep Learning Boost | + | - |
| Supported AI Software Frameworks | OpenVINO™, WindowsML, DirectML, ONNX RT, WebNN | - |
Security technologies
Core Ultra 7 251HX and Core i9-7900X technologies aimed at improving security, for example, by protecting against hacks.
| TXT | + | no data |
| EDB | + | + |
| OS Guard | + | no data |
Virtualization technologies
Virtual machine speed-up technologies supported by Core Ultra 7 251HX and Core i9-7900X 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 Ultra 7 251HX and Core i9-7900X. Depending on the motherboard, higher memory frequencies may be supported.
| Supported memory types | DDR5-6400 | DDR4 |
| Maximum memory size | 256 GB | 128 GB |
| Max memory channels | 2 | 4 |
| Maximum memory bandwidth | no data | 85.33 GB/s |
Graphics specifications
General parameters of integrated GPUs, if any.
| Integrated graphics card | Intel® Graphics | N/A |
| Quick Sync Video | + | - |
| Graphics max frequency | 1.8 GHz | no data |
Graphics interfaces
Available interfaces and connections of Core Ultra 7 251HX and Core i9-7900X integrated GPUs.
| Number of displays supported | 4 | no data |
Graphics image quality
Maximum display resolutions supported by Core Ultra 7 251HX and Core i9-7900X integrated GPUs, including resolutions over different interfaces.
| Max resolution over HDMI 1.4 | 4096 x 2304 @ 60Hz (HDMI 2.1 TMDS)7680 x 4320 @ 60Hz (HDMI 2.1 FRL) | no data |
| Max resolution over eDP | 3840 x 2400 @ 120Hz | no data |
| Max resolution over DisplayPort | 7680 x 4320 @ 60Hz | no data |
Graphics API support
APIs supported by Core Ultra 7 251HX and Core i9-7900X integrated GPUs, sometimes API versions are included.
| DirectX | 12 | no data |
| OpenGL | 4.5 | no data |
Peripherals
Specifications and connection of peripherals supported by Core Ultra 7 251HX and Core i9-7900X.
| PCIe version | 5.0 and 4.0 | 3.0 |
| PCI Express lanes | 24 | 44 |
Synthetic benchmarks
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.
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. Other than that, Passmark measures multi-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.
Pros & cons summary
| Performance score | 27.48 | 12.14 |
| Recency | 1 April 2026 | 26 June 2017 |
| Physical cores | 18 | 10 |
| Threads | 18 | 20 |
| Chip lithography | 3 nm | 14 nm |
| Power consumption (TDP) | 160 Watt | 140 Watt |
Ultra 7 251HX has a 126% higher aggregate performance score, an age advantage of 8 years, 80% more physical cores, and a 367% more advanced lithography process.
i9-7900X, on the other hand, has 11% more threads, and 14% lower power consumption.
The Intel Core Ultra 7 251HX is our recommended choice as it beats the Intel Core i9-7900X in performance tests.
Be aware that Core Ultra 7 251HX is a notebook processor while Core i9-7900X is a desktop one.
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