Intel Core i7-8086K vs Intel Core i5-8257U vs Intel Core i7-8700K

Intel Core i7-8086K

The Intel Core i7-8086K is a high-end desktop processor with six cores based on the Coffee Lake architecture and was announced in mid 2018. It is a limited edition for the 40 year X86 anniversary and at the time of announcement the fastest Coffee-Lake CPU. The processor clocks at between 3.7 and 5 GHz and can execute up to twelve threads simultaneously thanks to Hyper-Threading. According to Intel, the CPU is manufactured in an improved 14nm (14nm++) process. The i7-8086K is comparatively easy to overclock thanks to the unlocked multiplier. Compared to the cheaper i7-8700K (-66 Dollars) only the single core Turbo clock speed is faster (5 GHz versus 4.7 GHz).

Performance

Due to the two additional cores, performance has increased by almost 50% compared to the Core i7-7700K when all cores are in use. Compared to the cheaper Core i7-8700K, the 8086K offers only a higher single core Turbo Boost and therefore in daily usage and gaming not faster. As a high-end model, the i7-8086K is suitable for the most demanding applications and games.

Graphics

The integrated Intel UHD Graphics 630 iGPU is supposed to offer higher performance as its clock rate has been increased by 50 MHz. The build is identical to that of the Intel HD Graphics 630. We do expect a performance improvement, but as a low-end solution it will probably only display current games smoothly at reduced details - if at all.

Power Consumption

Intel specifies the TDP with 95 watts. Therefore, well-dimensioned cooling systems should easily manage to deal with the created heat. We expect increased efficiency due to the higher performance.

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 i7-8700K

The Intel Core i7-8700K is a high-end desktop processor with six cores based on the Coffee Lake architecture and was announced in September 2017. The processor clocks at between 3.7 and 4.7 GHz and can execute up to twelve threads simultaneously thanks to Hyper-Threading. According to Intel, the CPU is manufactured in an improved 14nm (14nm++) process. The i7-8700K is comparatively easy to overclock thanks to the unlocked multiplier.

Performance

Due to the two additional cores, performance has increased by almost 50% compared to the Core i7-7700K when all cores are in use. Single-core performance has not improved since its Kaby Lake predecessor. As a high-end model, the i7-8700K is suitable for the most demanding applications and games.

Graphics

The integrated Intel UHD Graphics 630 iGPU is supposed to offer higher performance as its clock rate has been increased by 50 MHz. The build is identical to that of the Intel HD Graphics 630. We do expect a performance improvement, but as a low-end solution it will probably only display current games smoothly at reduced details - if at all.

Power Consumption

Intel specifies the TDP with 95 watts. Therefore, well-dimensioned cooling systems should easily manage to deal with the created heat. We expect increased efficiency due to the higher performance.