Skylake

Skylake. Skylake is the codename for a microarchitecture designed by Intel as the successor to the Broadwell design. It was first launched in August 2015 and served as the foundation for the 6th generation Intel Core processors, representing a significant overhaul in platform technology. The architecture introduced a new socket and chipset, brought enhanced performance, and integrated more advanced graphics capabilities.

Overview

The Skylake microarchitecture was formally unveiled by Intel at the Intel Developer Forum in 2015, marking a "tock" in the company's then-prevailing Tick–tock model for semiconductor development. It succeeded the 14nm Broadwell processors and was manufactured using a refined version of the same process node. Key platform innovations included the introduction of the LGA 1151 socket paired with the Intel 100 Series chipsets, which brought support for DDR4 memory, PCI Express 3.0, and newer storage standards like NVMe. The launch encompassed a wide range of segments, from energy-efficient Y-series chips for 2-in-1 PCs to high-performance HEDT parts for the LGA 2066 platform, later branded under the Core X-series.

Architecture

The Skylake core design delivered improvements in instructions per cycle (IPC) through enhanced front-end, execution, and memory subsystems. It featured a new micro-op cache and improved branch prediction over its predecessor, Haswell. The architecture added support for new instruction set extensions, including Intel MPX for memory protection, Intel SGX for software guard extensions, and Intel TSX for transactional synchronization. The memory controller was upgraded to support both DDR3 and DDR4 standards, while the integrated Platform Controller Hub (PCH) provided extensive I/O connectivity via DMI and PCI Express. The design also incorporated advanced power management features for better efficiency across desktop, mobile, and server markets.

Processor list

The Skylake family was extensive, spanning multiple product lines and form factors. The consumer desktop lineup was led by the Core i7-6700K and Core i5-6600K unlocked processors for enthusiasts. For mobile computing, offerings included the Core i7-6820HQ for high-performance laptops and the ultra-low-power Core m7-6Y75 for fanless devices. The enterprise and workstation segment featured the Xeon E3-1200 v5 series for servers and the high-end Core i7-6950X Extreme Edition, a 10-core part for the LGA 2011-3 socket. Subsequent optimizations and refreshed steppings were released under the Kaby Lake and Coffee Lake codenames while retaining the foundational Skylake architecture.

Graphics

Skylake processors integrated the 9th generation of Intel HD Graphics, branded as HD Graphics 510, 515, 520, 530, and the more powerful Iris Graphics 540 and 550. The GPU architecture, known as Gen9, offered significant improvements in performance and features over the Gen8 graphics in Broadwell. It provided full hardware support for DirectX 12, OpenGL 4.4, and OpenCL 2.0, alongside enhanced media capabilities with dedicated fixed-function hardware for decoding and encoding HEVC/H.265 and VP9 video codecs. The highest-tier configurations, such as the Iris Pro Graphics 580 found in certain Core i7 chips, included 128MB of eDRAM (codenamed Crystal Well) acting as a Level 4 cache to boost both graphical and general compute performance.

Reception and impact

Upon release, Skylake was generally praised by reviewers and industry analysts for its solid performance gains, improved power efficiency, and the modernized platform with DDR4 support. It was seen as a substantial upgrade for users of older platforms like Sandy Bridge and Ivy Bridge. The architecture's longevity was notable; its core design was iteratively refined and used as the basis for several subsequent microarchitectures, including Kaby Lake, Coffee Lake, and even early Comet Lake processors. This extended lifespan underscored its efficiency and adaptability. Skylake's impact was also felt in the data center, with the Xeon Scalable Processor (codenamed Skylake-SP) architecture becoming a major force in the server market, competing directly with offerings from AMD and its EPYC lineup based on the Zen architecture.

Category:Intel microarchitectures Category:2015 in computing