Intel Core i7-1255U vs AMD Ryzen 7 5700U

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

The average 1255U in our database is in the same league as the Ryzen 5 5600U, as far as multi-thread benchmark scores are concerned. Which is nothing to be ashamed of, as of mid 2023.

Thanks to its decent cooling solution and a long-term CPU power limit of 28 W, the Spectre x360 13.5 14t-ef000 is among the fastest laptops built around the 1255U that we know of. It can be 20% faster in CPU-bound workloads than the slowest system featuring the same chip in our database, as of August 2023.

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 fourth-gen 10 nm process marketed as Intel 7 for decent, as of late 2022, energy efficiency.

AMD Ryzen 7 5700U

The AMD Ryzen 7 5700U is an APU of the Lucienne product family designed for leaner laptops. The Ryzen features eight Zen 2 cores clocked at 1.8 GHz (base clock speed) to 4.3 GHz (Boost) as well as a Vega 8 iGPU. Thread-doubling SMT tech is enabled in this CPU for up to 16 concurrent processing threads.

Architecture

In spite of what its name may suggest, Ryzen 7 5700U is not a Zen 3 part, meaning this is a Ryzen 4000 series mobile processor in disguise. Nevertheless, the CPU is manufactured on the modern 7 nm TSMC process and its performance as well as energy efficiency figures are very strong compared to what Intel currently has to offer in this segment.

The Ryzen 7 features 8 MB of Level 3 cache. Its built-in memory controller is designed to work with dual-channel DDR4-3200 or quad-channel LPDDR4-4266 RAM. Unlike the desktop Ryzen 5000 processors, Ryzen 7 5700U does not support PCI-Express 4.0, meaning those speedy NVMe SSDs will be limited to read/write rates of 3.9 GB/s.

The Ryzen gets soldered directly to the motherboard (FP6 socket) and is thus not user-replaceable.

Performance

The average 5700U in our database is in the same league as the Ryzen 7 4800U, Ryzen 7 PRO 5850U, Core i7-1365U, as far as multi-thread benchmark scores are concerned.

Thanks to its decent cooling solution and a long-term CPU power limit of 35 W, the Schenker VIA 15 Pro is among the fastest laptops built around the 5700U that we know of. It can be roughly 50% faster in CPU-bound workloads than the slowest system featuring the same chip in our database, as of August 2023.

Graphics

In addition to its eight CPU cores, Ryzen 7 5700U features a Radeon RX Vega series graphics adapter with 8 CUs (= 512 shaders) running at up to 1,900 MHz. This iGPU trails behind the 96 EU Intel Iris Xe Graphics G7 in synthetic benchmarks, yet its real-world performance is good enough for many games released in 2020 and 2021 at reasonable resolutions (up to Full HD 1080p) and low to medium quality. As the Vega has no VRAM of its own, it is paramount that fast system RAM is used.

The graphics adapter definitely supports UHD 2160p monitors at 60 Hz, and will gladly HW-decode AVC, HEVC and VP9-encoded videos. There is no AV1 support here though.

Power consumption

This Ryzen 7 has a default TDP, also known as the long-term power limit, of 15 W; laptop makers are free to change that to anything between 10 W and 25 W, with clock speeds and performance changing accordingly as a result. Most companies will go for a higher value to extract more performance out of the APU. By choosing the lowest value, it will be possible to build a passively cooled system around the chip, too.

The 7 nm TSMC process the R7 5700U is built with makes for decent, as of late 2022, energy efficiency.