Intel Core i7-1255U

The Intel Core i7-1255U is a high-end mobile CPU for thin and light laptops based on the Alder Lake architecture. It was announced in early 2022 and offers 2  performance cores (P-cores, Golden Cove architecture) and 8 efficient cores (E-cores, Gracemont architecture). The P-cores support Hyper-Threading leading to 12 supported threads when combined with the E-cores. The clock rate ranges from 1.7 to 4.7 GHz on the performance cluster and 1.2 to 3.5 GHz on the efficient cluster. The performance of the E-cores should be similar to old Skylake cores (compare to the Core i7-6700HQ). All cores can use up to 12 MB L3 cache. Compared to the i7-1265U (fastest U-series CPU at launch), the 1255 offers 100 MHz lower clocked CPU cores and only "Essentials" vPro management features. Compared to the P-series (28W) or H-series (45W), the 15W TDP may limit the sustained performance.

Performance

Thanks to the 10 cores, the multi-threaded performance should be clearly faster than the older quad-core Tiger Lake CPUs with 15 Watt (like the Intel Core i7-1160G7). The sustained performance will be limited by the TDP setting and thermals and therefore only short term loads. Thanks to the architectural improvements of the big Golden Cove cores, the single thread performance should be better than similar clocked Tiger Lake CPUs.

Architecture

The integrated memory controller supports various memory types up to DDR5-4800, DDR4-3200, LPDDR5-5200, and LPDDR4x-4267. The Thread Director (in hardware) can support the operating system to decide which thread to use on the performance or efficient cores for the best performance. For AI tasks, the CPU also integrates GNA 3.0 and DL Boost (via AVX2). Quick Sync in version 8 is the same as in the Rocket Lake CPUs and supports MPEG-2, AVC, VC-1 decode, JPEG, VP8 decode, VP9, HEVC, and AV1 decode in hardware. The CPU only supports PCIe 4.0 (x8 for a GPU and two x4 for SSDs).

The integrated graphics card is based on the Xe-architecture and offers all 96 EUs (Execution Units) operating at up to 1.25 GHz.

Power consumption

This Core i7 has a "minimum assured" power consumption of 12 W. Its Base power consumption sits at 15 W and its maximum Intel-recommended Turbo power consumption isn't supposed to exceed 55 W. All those values are too high to allow for pasisvely cooled designs.

Last but not the least, Core i7-1255U is built with Intel's third-gen 10 nm process marketed as Intel 7 for decent, as of late 2022, energy efficiency.

Series	Intel Alder Lake-M
Codename	Alder Lake-U
Series: Alder Lake-M Alder Lake-U Intel Core i7-1265U 1.3 - 4.8 GHz 10 / 12  12 MB L3 Intel Core i7-1255U « 1.2 - 4.7 GHz 10 / 12  12 MB L3 Intel Core i5-1245U 1.2 - 4.4 GHz 10 / 12  12 MB L3 Intel Core i5-1235U 0.9 - 4.4 GHz 10 / 12  12 MB L3 Intel Core i7-1260U 0.8 - 4.7 GHz 10 / 12  12 MB L3 Intel Core i7-1250U 0.8 - 4.7 GHz 10 / 12  12 MB L3 Intel Core i5-1240U 0.8 - 4.4 GHz 10 / 12  12 MB L3 Intel Core i5-1230U 0.7 - 4.4 GHz 10 / 12  12 MB L3 Intel Core i3-1215U 0.9 - 4.4 GHz 6 / 8  10 MB L3 Intel Pentium 8505 0.9 - 4.4 GHz 5 / 6  8 MB L3 Intel Core i3-1210U 0.7 - 4.4 GHz 6 / 8  10 MB L3 Intel Pentium 8500 0.7 - 4.4 GHz 5 / 6  8 MB L3 Intel Celeron 7305 0.9 - 1.1 GHz 5 / 5  8 MB L3 Intel Celeron 7300 0.7 - 1 GHz 5 / 5  8 MB L3
Clock Rate	1200 - 4700 MHz
Level 1 Cache	928 KB
Level 2 Cache	9.5 MB
Level 3 Cache	12 MB
Number of Cores / Threads	10 / 12
Power Consumption (TDP = Thermal Design Power)	15 Watt
Manufacturing Technology	10 nm
Max. Temperature	100 °C
Socket	BGA1744
Features	Thread Director
GPU	Intel Iris Xe Graphics G7 96EUs ( - 1250 MHz)
64 Bit	64 Bit support
Architecture	x86
Announcement Date	01/04/2022
Product Link (external)	Intel Alder Lake-M i7-1255U

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