Intel Core i7-8650U vs Intel Core i7-5600U

Intel Core i7-8650U

The Intel Core i7-8650U 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 i7-7600U, which were still dual-cores, the i7-8650U is equipped with four cores but at a lower base frequency of 1.9 GHz. The Turbo Boost can go up to 4,2 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 behaviour 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. The performance however is highly depending on the TDP settings and cooling solution of the laptop. Especially, longer loads will show varying results in different laptops.

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 i7-5600U

The Intel Core i7-5600U is an ULV (ultra low voltage) dual-core processor based on the Broadwell architecture, which has been launched in January 2015. In addition to two CPU cores with Hyper-Threading clocked at 2.6 - 3.2 GHz (2 Cores: 3.1 GHz), the chip also integrates an HD Graphics 5500 GPU and a dual-channel DDR3(L)-1600 memory controller. The Core i7 is manufactured in a 14 nm process with FinFET transistors.

Compared to the Core i7-5650U, the i7-5600U features a higher CPU base clock, but integrates a somewhat slower GPU.

Architecture

Broadwell represents the "Tick" in Intel's Tick-Tock model, which means a shrink of its predecessor Haswell. The new 14 nm manufacturing process with three-dimensional FinFET transistors allows not only improvements in energy efficiency, but also a significantly smaller die size fit for more compact packages and devices.

Further advantages result from the revised microarchitecture of Broadwell. Due to its improved branch prediction, bigger buffer sizes (1500 instead of 1000 entries in the L2 TLB) and other tweaks, the performance per clock has been increased by more than 5 percent over its predecessor. There are also some new instruction set extensions designed for cryptographic applications.

Performance

Thanks to its improved architecture, the Core i7-5600U is about 5 - 20 percent faster than the slightly lower clocked Core i7-4600U (Haswell, 15 W) and matches the Core i5-4288U (Haswell, 28 W). Thus, the CPU has sufficient power even for demanding applications and multitasking.

Graphics

The integrated HD Graphics 5500 offers 24 Execution Units (EUs) clocked at 300 - 950 MHz. Similar to the CPU core, the GPU architecture (Intel Gen 8) has been thoroughly revised for improved performance-per-clock. The HD Graphics 5500 beats the HD Graphics 4400 (20 EUs) as well as the HD Graphics 5000 (40 EUs), both part of the Haswell generation. Nevertheless, most games as of 2015 will be playable only in low settings.

Broadwell is the first Intel chip to fully support DirectX 11.2 as well as OpenCL 1.3/2.0 and OpenGL 4.3. Video will output natively via DisplayPort 1.2 or HDMI 1.4a. However, the new HDMI 2.0 standard is not supported.

Power Consumption

The i7-5600U is rated at a TDP of 15 W (7.5 W cTDP Down) including the graphics card, memory controller, VRMs and the integrated chipset. Therefore, the CPU is suited even for small ultrabooks 11-inches and greater.