AMD - Update

AMD's resurgence in the desktop CPU space can be attributed to a three-letter word: Zen.

The revolutionary microarchitecture, introduced in 2017, has paved the way for a complete range of high-performance CPUs, extending from entry-level Ryzen 3 right the way through to high-end Ryzen Threadripper. It wouldn't be a stretch to suggest that Zen-based CPUs have served as a primary catalyst for PC innovation in the past 18 months, and a key contributor to the industry's transition to many-core computing.

Zen: an architecture for today and tomorrow

Described by AMD as a 'clean-sheet' design, the 14nm Zen microarchitecture has been built from the ground up to deliver a greater-than 50 per cent improvement in IPC (instructions-per-clock) over previous-generation AMD hardware. Such a feat requires a forward-looking design that will stand the test of time, and Zen comes equipped with a bevy of under-the-hood improvements that contribute to what is an efficient and versatile foundation.

Geared for the workloads of both today and tomorrow, Zen benefits from vastly-improved branch prediction, made possible through machine learning, and a new op-cache buffer that can store eight instructions and dispatch six, signalling another 50 per cent increase over earlier Bulldozer cores. Removing bottlenecks is key to driving greater efficiency, and to that end Zen has doubled the number of ALUs (arithmetic logic units) per thread from two to four, with wider queues allowing for more instructions to be loaded and retired than previously possible.

The aforementioned are just some of the improvements that bolster single-thread performance, and AMD also touts significant multi-threaded benefits by eschewing the CMT (clustered multi-thread) design used in previous-generation architectures in favour of superior SMT (simultaneous multi-threading) technology. Allowing for two threads per physical core, SMT can enable a performance increase of as much as 41 per cent in certain workloads.

Given the upgrades to the core, a better cache structure is essential, and Zen obliges with a 2x increase in L1 and L2 bandwidth, as well as a 5x increase in L3 performance. Furthermore, the L1 cache is upgraded from write-through to write-back, ensuring higher bandwidth and reduced latency, and Zen achieves impressive flexibility by building four cores as well as the associated caches and controllers into a single Core Complex (CCX). Processors with more than four cores stitch multiple CCXs together using an innovative new interconnect dubbed Infinity Fabric, leading the way for many-core CPUs, as well as the ability to integrate graphics on certain SKUs.

All that's needed to complete the Zen jigsaw is SenseMI, a collection of innovative technologies that allow each Ryzen processor to maximise efficiency using hundreds of sensors that are tasked with tailoring performance to the current workload. XFR (Extended Frequency Range) provides automatic clock-speed scaling based on cooling capability, Precision Boost can modulate performance in real time using 25MHz increments, and using Neural Net Prediction, each Ryzen processor is equipped with AI that enhances efficiency by anticipating what lies ahead in any given workload. Smart, efficient, and progressive.

Ryzen 2: taking Zen to the next level

Appreciating the pace at which modern technology progresses, AMD isn't resting on its laurels and introduced the successor to the Zen architecture in April 2018. Codenamed Zen+, the second-generation refresh revolves around a 12nm die shrink that enables evolutionary improvements to an already-solid foundation.

Chief among the upgrades are higher frequencies, with the 12nm fabrication process enabling up to 300MHz additional headroom at the same power target. Bolstering the performance advantage is Precision Boost 2, which upgrades first-generation Zen technology to maintain higher speeds on as many cores as possible. Whereas Zen's Precision Boost would automatically modulate performance on up to two cores, Zen+'s use of Precision Boost 2 and XFR2 monitors conditions and dynamically scales frequency in 25MHz increments on any number of CPU cores, delivering maximum efficiency and superior optimisation.

Higher speeds and power savings are always welcome, and AMD has also used the 12nm refresh to re-examine memory latency. Helping accelerate IPC, Zen+ reduces L1 cache latency by 13 per cent, L2 by 34 per cent, and L3 by 16 per cent. Coupled with support for faster DDR4 memory, these incremental upgrades all combine to ensure that Ryzen 2000-series processors, based on the Zen+ architecture, can deliver up to a 10 per cent increase in overall performance.

Ryzen Mobile: Zen meets Vega

Proving that the Zen architecture is as adaptable as they come, a range of Ryzen Mobile processors now combine the goodness of the Zen processor core with best-in-class AMD Vega graphics. Ideally suited to ultra-thin multimedia laptops, processors such as the Ryzen 7 2700U are a great fit thanks to an enviable mix of four Zen+ cores and onboard Radeon RX Vega 10 graphics.

Delivered in a single, efficient 15W package, the mobile Ryzen processor harnesses the strengths of the Zen architecture, meaning excellent multi-tasking capabilities aided by simultaneous multi-threading (SMT), while SenseMI gives users an optimal balance between responsive performance and all-day battery life.

Bolstering the credentials of the CPU component, Radeon RX Vega adds latest-generation graphics to the equation, bringing smooth and playable gaming to super-sleek laptops, as well as support for cutting-edge technologies such as 4K, HDR, and FreeSync 2 adaptive-framerate synchronisation. Such characteristics have led to design wins from all the major players - including Acer, Dell, HP and Lenovo - and whether you're looking for a mobile PC for work or play, Ryzen Mobile means there's no need to compromise.

More cores, not more cost

The arrival of the Zen architecture has smoothed the way toward many-core computing for PC users from all walks of life. Restoring competition and innovation to the CPU space, Ryzen processors have raised the bar for core count, bringing years of dual- or quad-core stagnation to an end. Entry-level Ryzen 3 brings quad-core computing to the budget segment, mainstream Ryzen 5 offers hexa-core performance for the masses, while Ryzen 7 touts octo-core credentials from as little as £210.

Demonstrating that innovation needn't stop there, the many-core race has been blown wide open by Ryzen Threadripper, a range of HEDT (high-end desktop) parts offering up to a staggering 32 cores and 64 threads in a single package. What's important for consumers seeking a genuine reason to upgrade is that the entire Ryzen range, from Ryzen 3 right the way up to Threadripper, tends to offer more cores and threads than the competition at similar price points. With Zen, there's no need to be restricted to premium dual-core CPUs any longer; the era of affordable many-core processors is officially here.