Intel Core i5-8250U vs Intel Core i5-8400H

Intel Core i5-8250U

The Intel Core i5-8250U 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 predecessor the Core i5-7200U, which were still dual-cores, the i7-8250U is equipped with four cores but at a lower base frequency of 1.6 GHz. The Turbo Boost can go up to 3,4 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

According to Intel, the new quad core models are up to 40% faster than their dual core predecessors. Due to the reduced TDP and the same 14nm+ process, the long term performance and throttling behavior will be interesting and depending on the laptop design. Therefore, the older 35 Watt quad-core models should be faster in applications that demand longer CPU loads.

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 i5-8400H

The Intel Core i5-8400H is a high-end processor for laptops with four cores based on the Coffee Lake architecture and will be announced early 2018. The processor clocks at between 2.5 and 4.2 GHz (4.1 with 4 cores) and can execute up to eight threads simultaneously thanks to Hyper-Threading. According to Intel, the CPU is manufactured in an improved 14nm (14nm++) process.

The Coffee Lake architecture is similar to Kaby Lake and differs only in the amount of cores (now six cores for the high end versions) and the improved 14nm process (14nm++ according to Intel).

Performance

The Intel Core i5-8400H should perform similar as the older Core i7-7920HQ (3.1 - 4.1 GHz). The faster Coffee Lake CPUs, like the Core i7-8750H offers two additional cores and is therefore up to 50% faster in multithreaded benchmarks. Still, the performance of the i5-8400H should be sufficient for even demanding applications and games.

Graphics

The integrated Intel UHD Graphics 630 iGPU is supposed to offer a slightly higher performance as its clock rate has been increased by 50 MHz (rumored). The architecture 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 45 watts and therefore the i5 is only suited for big laptops with good cooling solutions. Using cTDP-down, the CPU can also be configured to 35 Watt resulting in a reduced performance.