Intel Celeron 7305 vs Intel Atom x7-Z8700 vs Intel Core i7-1255U

Intel Celeron 7305

The Intel Celeron 7305 is an entry-level mobile CPU for thin and light laptops based on the Alder Lake architecture. It was announced in early 2022 and offers one performance core (P-cores, Golden Cove architecture) and 4 efficient cores (E-cores, Gracemont architecture). The CPU does not support HyperThreading leading to only 5 supported threads at once. The clock rate of the performance cluster is 1100 MHz, the one of the efficient cluster is 900 MHz. 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 8 MB L3-cache. Compared to the faster Core i3-1215U, the Celeron offers one less P-core and lower clock speeds (no Turbo).

Performance

Thanks to the 5 cores, the multi-threaded performance should be clearly faster than the older dual-core Tiger Lake CPUs with 15 Watt (like the Intel Core i3-1115G4). However, due to the missing Turbo and the low clock speed, the single core performance will be very low.

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 48 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. power (PL2). The minimum assured power is 12 Watt. The whole SoC is manufactured in a 10nm process at Intel, which is known as Intel 7.

Intel Atom x7-Z8700

The Intel Atom x7-Z8700 is a power efficient quad-core SoC for Windows and Android devices (tablets and convertibles), which has been presented in March 2015. It is clocked at 1.6 - 2.4 GHz and part of the Cherry Trail platform. Thanks to its new 14 nanometer low-power process (P1273) with tri-gate transistors, energy efficiency has been significantly improved compared to its predecessor Bay Trail-T (e.g. Atom Z3795). In addition to the CPU cores, the SoC offers a DirectX 11.2-capable GPU as well as a LPDDR3 Memory Controller (2x 64 bit, 25.6 GB/s).

Architecture

The processor cores are based on the Airmont architecture, which is basically a slightly modified shrink of the previous Silvermont core. While performance per clock has not been improved, the more efficient 14 nm process leads to a better utilization of the CPU Burst (alias Turbo Boost) and a therefore somewhat higher overall performance.

Performance

Compared to the Atom Z3795, the Atom x7-Z8700 offers about 5 percent more performance and is similar fast as an AMD A6-6210 APU or high-end ARM SoCs, e.g. the Snapdragon 810 or Exynos 7420.

Using Windows, the performance is adequate for everyday tasks such as Internet or Office, but not for very complex software or modern games.

Graphics

The HD Graphics (Cherry Trail) is based on the Intel Gen8 architecture, which supports DirectX 11.2 and is also found in the Broadwell series (e.g. HD Graphics 5300). With 16 EUs (Execution Units) and a clock speed of up to 600 MHz, the GPU is about twice as fast as the HD Graphics (Bay Trail) and will handle older and less demandig Windows games (e.g. Counter-Strike: GO) in low settings at decent frame rates. The GPU also supports 4K/H.265 video acceleration.

Compared to ARM SoCs, the HD Graphics offers a performance somewhere between the Qualcomm Adreno 330 / PowerVR G6430 and the Adreno 420 / PowerVR GX6450.

Power Consumption

The entire SoC is rated at an SDP of 2 watts, which indicates a TDP of less than 4 watts. Thus, the chip can be used in passively cooled tablets.

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.