Intel Core i7-8550U vs Intel Core i3-1215U vs Intel Core i7-1255U

Intel Core i7-8550U

The Intel Core i7-8550U is a power efficient quad-core SoC for notebooks and Ultrabooks based on the Kaby Lake Refresh generation and was announced in August 2017. Contrary to its direct predecessors Core i7-7500U and i5-7260U, respectively, which were still dual-cores, the i7-8550U is equipped with four cores but at a lower base frequency of 1.8 GHz. The Turbo Boost is not specified yet, but should be at least 3.7 - 4 GHz and therefore also offer good short term single core speeds. The GPU is now named Intel UHD Graphics 620 but otherwise identical to the Intel HD Graphics 620. The integrated memory controller supports DDR4-2400 / LPDDR3-2133 and dual channel memory.

Architecture

Intel basically uses the same micro architecture compared to Skylake, so the per-MHz performance does not differ. The manufacturer only reworked the Speed Shift technology for faster dynamic adjustments of voltages and clocks, and the improved 14nm process allows much higher frequencies combined with better efficiency than before.

Performance

The performance of the i7-8550U depends on the cooling solution of the laptop and the defined TDP limits for short and long term performance. This leads to big differences in our benchmark scores ranging from the 15 Watt reference by Intel up to the 23% higher score of the Inspiron 17-7773 in the Cinebench R15 Multi benchmark. Especially when taxing the CPU for longer periods, these differences can be even higher.

In our usual benchmarks, the average i7-8550U is as fast as the 35 Watt rated Core i5-7440HQ. For single thread performance, the high Turbo Boost frequency helps achieving one of the highest scores for mobile CPUs.

Graphics

The integrated Intel UHD Graphics 620 (Intel Gen 9.5) is untouched from the 8th Gen Kaby Lake chips. With fast dual-channel memory it can reach the performance of a dedicated GeForce 920M.

Contrary to Skylake, Kaby lake now also supports H.265/HEVC Main 10 with a 10-bit color depth as well as Google's VP9 codec. The dual-core Kaby Lake processors announced in January should also support HDCP 2.2.

Power Consumption

The chip is manufactured in an improved 14nm process with FinFET transistors (14nm+), the same as the 7th Gen Kaby Lake processors. Intel still specifies the TDP with 15 Watts, which is typical for ULV chips. Depending on the usage scenario, the TDP can vary between 7.5 (cTDP Down) and 25 Watts.

Intel Core i3-1215U

The Intel Core i3-1215U is a mid-range 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 4 efficient cores (E-cores, Gracemont architecture). The P-cores support Hyper-Threading leading to 8 supported threads when combined with the E-cores. The clock rate ranges from 1.2 to 4.4 GHz on the performance cluster and 0.9 to 3.3 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 10 MB L3-cache. Compared to the faster i5 and i7 models, the i3 does not include vPro features.

Performance

The average 1215U in our database is in the same league as the Ryzen 3 5300U and also the Core i7-1185G7, as far as multi-thread benchmark scores are concerned. This is decent enough of a result, as of late 2022. For an entry-level CPU, that is.

Your mileage may vary depending on how competent the cooling solution of your laptop is, and how high the CPU power limits are.

Features

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 64 of the 96 EUs (Execution Units) operating at up to 1.1 GHz.

The CPU is rated at 15 W base power (TDP, PL1) and 55 W max. Turbo power (PL2) and the whole SoC is manufactured in a 10nm process at Intel, which is known as Intel 7.

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.