Intel Celeron 5305U vs Intel Core i7-1255U vs Intel Celeron 5205U

Intel Celeron 5305U

The Intel Celeron 5305U is a low-power dual-core SoC for laptops, based on the Comet Lake architecture, which was introduced in 2020. Compared to Kaby Lake and Whiskey Lake, there are apparently no differences with Comet Lake apart from the two additional cores in the Top model Core i7-10710U. The processor is still manufactured using the mature 14nm process (14nm++ like Whiskey Lake). The processor cores clock at a fixed 2.3 GHz (no Turbo) and also only offer 2 threads (no HyperThreading). Compared to the more powerful Core i3, i5 and i7 variants, the Celeron does not offer SSE (2) support.

You can find more information about the Comet Lake architecture and the available processors on our Comet Lake topic page.

According to Intel, the integrated graphics card is called Intel UHD Graphics, but is an old Intel UHD Graphics 610. It is clocked in the Celeron 5205U at 300 - 900 MHz and is only sufficient for very demanding games. The CPU also offers an integrated DDR4-2666 / LPDDR4x 2933 / LPDDR3-2133 dual-channel memory controller as well as VP9 and H.265 video decoder and encoder.

Performance

The performance of the Celeron 5305U is in the lowest entry-level class of notebook processors in 2020. Due to the lack of Turbo and only 2 cores, the CPU cannot score points in either single-core or multi-core tasks. The processor is therefore only suitable for undemanding tasks such as surfing with a few tabs and office tasks.

The power consumption and performance can be set from 15 to 12.5 watts by the notebook manufacturer via cTDP-down. However, the processor then only runs at 800 MHz and significantly reduced performance. Even at 15 watts, however, the processor is suitable for thin and light notebooks.

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.

Intel Celeron 5205U

The Intel Celeron 5205U is a power efficient entry-level dual-core SoC for notebooks based on the Comet Lake (CML-U) generation and was announced in October 2019. Compared to the similar Whiskey Lake Celeron 4205U processors, the difference is the higher clock speed (+100 MHz) and support for faster memory. The processor cores are clocked at only 1.9 GHz (no Turbo) and don't support SMT / HyperThreading (so only 2 threads). More information on Comet Lake and all the models and articles on it can be found here.

The integrated graphics adapter is still the same as in the previous generations. It is called only Intel UHD Graphics but is still the same Intel UHD Graphics 610 like in the Pentium 4205U. Furthermore, the SoC integrates a VP9 and H.265 de- and encoder and an integrated dual channel LPDDR3-2133/DDR4-2400 memory controller (compared to DDR4-2666 in the faster and costlier Core i3/i5/i7 processors).

Performance

While we have not tested a single system powered by the 5205U as of August 2023, it's safe to expect the chip to be about half as fast as the Core i3-10110U (Comet Lake, 2 cores, 4 threads, up to 4.1 GHz). Which is nothing to write home about, really, as of mid 2022.

Power consumption

This Celeron has a default TDP, also known as the long-term power limit, of 15 W. Intel officialy allows laptop manufacturers to reduce that value somewhat, 12.5 W being the lower limit, resulting in lower clock speeds and lower performance. Unlike most Comet Lake family processors, Celeron 5205U is fairly likely to actually stick to that limitation as its cores are not Boost-enabled.

Last but not the least, this CPU is manufactured on an old, as of late 2022, 14 nm Intel process making for subpar energy efficiency.