Intel Core i5-8257U vs Intel Core i5-7Y54 vs Intel Core i7-8559U

Intel Core i5-8257U

The Intel Core i5-8257U is a quad-core SoC for notebooks based on the Coffee Lake architecture that was announced in the new entry level MacBook Pro 13 in mid 2019. Compared to its predecessor, the CPU is now a quad-core with Hyperthreading support for the execution of up to 8 threads simultaneously. The base frequency is only 1.4 GHz, but the Turbo goes all the way up to 3.9 GHz. It is also equipped with an Intel Iris Plus Graphics 645 GPU with 128 MB eDRAM, a dual-channel memory controller (DDR4) as well as VP9 and H.265 video decoding as well as encoding. The chip is still manufactured in a 14nm process with FinFET transistors.

Compared to faster Core i7-8557U model with eDRAM and 15 Watts, the i5-8257U only features 6 MB smart cache and the slowest clock of the Iris Plus GPU.

Architecture

Intel basically uses the same micro architecture compared to Kaby Lake, 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

Thanks to the relative high Turbo Boost clock, the single thread performance should be very good, but still behind the faster i7 model. The short burst all core performance is clearly better compared to the old dual core predecessors thanks to the additional cores. In sustained workloads, the performance is usually limited by the TDP and cooling. In these workloads the difference to the Core i7 should be also smaller.

Graphics

The integrated Intel Iris Plus 645 Graphics is the GT3e model of the Coffee Lake GPU (Intel Gen. 9.5). It has 48 Execution Units running at 300-1050 MHz and the performance is comparable to a GeForce 930M or 940MX thanks to fast eDRAM cache. However, there aren't any significant improvements compared to the old Iris Plus 650, so modern games can often not be played smoothly or only at the lowest or medium settings, respectively.

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, which improves the efficiency even further. Intel specifies the TDP with 15 Watts and therefore suited for thin and light laptops.

Intel Core i5-7Y54

The Intel Core i5-7Y54 is a very efficient dual-core SoC for tablets and passively cooled notebooks based on the Kaby Lake architecture and was announced in the end of August 2016. The CPU consists of two processor cores clocked at 1.2-3.2 GHz (2-core Turbo not specified yet). Thanks to Hyper Threading, the processor can execute up to four threads simultaneously. The chips also includes the Intel HD Graphics 615 GPU, a dual-channel memory controller (DDR3L/LPDDR3) as well as VP9 and H.265 video de- and encoder. It is still produced in a 14 nm process with FinFET transistors. 

Architecture

Intel basically used the familiar micro architecture from the Skylake generation, so the per-MHz performance is identical. Only the Speed-Shift technology for faster dynamic adjustments of the voltages and clocks was improved, and the matured 14 nm process now also enables much higher frequencies and better efficiency than before. 

Performance

Despite the changed designation, the Core i5-7Y54 is the successor to the Core m5-6Y54 (Skylake Y-series), so the chip does not reach the performance level of other Core i processors due to the lower TDP. Thanks to its high Turbo clock, the 7Y54 can sometimes keep up with the 15 Watt models for short peak load and single-thread scenarios, but the clocks will drop significantly under sustained workloads. The CPU is still suitable for many more demanding applications as well as multitasking. 

Graphics

The integrated Intel HD Graphics 615 GPU has 24 Execution Units (EUs) like the old HD Graphics 515 and runs with clocks between 300 and 950 MHz in combination with this processor. The performance heavily depends on the TDP limit as well as the memory configuration; with fast LPDDR3-1866 RAM in dual-channel mode, the GPU should sometimes be able to compete with the HD Graphics 520, but can also be much slower in other scenarios. Modern games from 2016 will, if at all, only run smoothly in the lowest settings.

Contrary to Skylake, Kaby Lake now also supports hardware decoding for H.265/HEVC Main10 with a 10-bit color depth as well as Google's VP9 codec.

Power Consumption

The chip is manufactured in an improved 14 nm process with FinFET transistors, so the power efficiency was once again improved significantly. The typical TDP for the Y-series is specified at 4.5 Watts, and can be adjusted in both directions depending on the usage scenario.

Intel Core i7-8559U