The Intel Core i5-5257U is a fast dual-core processor based on the Broadwell architecture, which has been launched in January 2015. With a TDP of 28 W, the CPU is suited for medium-sized ultrabooks and notebooks (MacBook Pro 13), whereas smaller devices will use more power efficient ULV models such as the Core i5-5200U (15 W TDP). In addition to two CPU cores with Hyper-Threading clocked at 2.7 - 3.1 GHz (2 Cores: 3.1 GHz as well), the chip also integrates an Iris Graphics 6100 GPU and a dual-channel LPDDR3-1866/DDR3L-1600 memory controller. The Core i5 is manufactured in a 14 nm process with FinFET transistors.
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.
Thanks to its improved architecture, the Core i5-5257U almost matches the slightly higher clocked predecessors Core i7-4558U and Core i5-4308U (Haswell, 28 W). Thus, the CPU has sufficient power even for demanding applications and multitasking.
The integrated Iris Graphics 6100 offers 48 Execution Units (EUs) clocked at 300 - 1050 MHz. Similar to the CPU core, the GPU architecture (Intel Gen 8) has been thoroughly revised for improved performance-per-clock. In addition, the GPU benefits from faster memory speeds up to LPDDR3-1866 (Haswell: DDR3-1600). Overall, the Iris Graphics 6100 is about 20 - 25 percent faster than the former Iris Graphics 5100. Nevertheless, demanding games as of 2015 will be playable only in low or medium 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 officially supported.
The i5-5257U is rated at a TDP of 28 W including the graphics card, memory controller, VRMs and the integrated chipset. Therefore, the CPU is suited for medium-sized ultrabooks 13-inches or greater.