AMD TEARS UP THE HIGH-END CPU RULEBOOK
After years of Intel dominance, AMD is back with a true top-end multi-threaded beast in the form of Ryzen Threadripper. Josh Collins dives deep into the nuances of AMD’s latest Zen-based CPUs.
After years of Intel dominance, AMD is back with a true top-end multi-threaded beast in the form of Ryzen Threadripper. We dive deep into the nuances of AMD’s latest Zen-based CPUs.
The Big Boy of the Ryzen product range has finally landed in the APC lab! The Threadripper 1950X and 1920X have been put through the rigors of our testing, along with three AMD X399-based motherboards from ASUS, Gigabyte and MSI. Before we get to those, however, let’s take a closer look at some details for AMD’s new CPU, what it brings to the market and the impact felt by the performance and opportunity presented against the Blue Giant competition.
The AMD X399 chipset paired with a Ryzen Threadripper CPU heralds the introduction of AMD’s first high-end desktop (HEDT) platform. The market was first created by Intel utilising the X58 chipset and associated CPUs utilising technology and architectural fundamentals drawn from the server product space. The HEDT concept introduced high core counts, and increased memory channels and density, platform I/O resources, as well as performance for workstation-type workloads compared to previous consumer-orientated platforms (P45 and X48, followed by P67/Z68). Paired with the ability to support extensive multi-GPU configurations, the HEDT platform direction created the origins for a high-end experience that would be further refined and defined over almost a decade and numerous platform generational updates.
TO DIE FOR
After years of effectively no HEDT competition, AMD has now entered the fray with the Ryzen Threadripper and X399, utilising CPU architecture derived from AMD’s Epyc server range. The Epyc processors utilise a four-die structure, interconnecting dies based on the Zen micro-architecture. This structure delivers 8 cores/16 threads, two memory channels and 32 PCIe lanes per die for a subsequent potential total of 64 cores/128 threads, eight memory channels and 128 PCIe lanes available for Epyc 1P solutions.
With Threadripper designed as a 1P HEDT platform with quad-channel memory, the Epyc processor design has been applied to the Threadripper rollout but with two dies disabled. This creates a maximum potential of 16 cores/32 threads, quad-channel memory support
and 64 PCIe lanes. This spec is found in the product-range-topping Ryzen Threadripper 1950X. The 1920X has a lowered core and thread count of 12 and 24, respectively, but retains the overall platform resource availability of quadchannel memory and 64 PCIe lanes. Launching slightly later will be the 8-core, 16-thread 1900X.
CREATOR MODE VS GAME MODE
These modes are two software-set functions for the Threadripper range implemented via the AMD Ryzen Master Threadripper Edition software. The need to differentiate between two modes was developed during pre-release R&D as in-house testing revealed there was an install-base of gaming titles that, due to the way the game code was developed, may have performance deficits when addressing a broad memory and core architecture along with either working better with a lower core count or demonstrating a hard limit that can’t be exceeded (ie, >20 processing threads).
Creator Mode essentially delivers CPU specs as per the originally intended design for Threadripper with resources distributed across the cores, and all cores and threads readily available for any workloads to be crossed between the processor dies utilising the Infinity Fabric. The Infinity Fabric, in layman’s terms, is an internal communication architecture interconnecting processor resources present on the AMD Ryzen SoC design and interacts with the AMD SenseMI technology. Essentially, the Infinity Fabric and SenseMI are the brain and nervous system behind the computational heart of the processor.
Game Mode disables half of the available core and thread count, but does so in a rather neat and clever way — using a switch in the easily navigated Ryzen Master software suite, that then requires a system reboot. Contrary to initial logical conclusion, the cores (and thereby threads) are not physically disabled to achieve this drop in core and thread count; nor is simultaneous multithreading (SMT) disabled. The reason for this approach is that physical disablement would remove platform resources delivered by the die, such as memory channel, USB and PCIe allocations, and removing SMT would also be a detrimental move on the overall performance.
To circumvent the loss of resources and performance via disabling cores and SMT for Game Mode, what Ryzen Master is doing is issuing a BCDEdit command to the operating system configuration registry and changing the numproc value. This eloquent solution lowers the perceived (and functional) core and thread count, without negatively impacting SMT functionality or processor die resources, while circumventing the problem presented by some gaming titles. Bravo, AMD, for creating a simple, clever workaround for the end user and delivering a functional choice.
I/O YOU
Pitched as “Unlocked. Unrestrained. Uncompromised.”, AMD was seemingly going for a big impact, and perhaps even Intel’s throat, especially given the frosty reception of the specs for Intel’s heavily segmented X-series product stack recently launched on the X299 platform. Unlike Intel’s X-series processors that see desirable HEDT CPU product specs costing an arm or a leg, by comparison, AMD’s Threadripper range provides the same platform resources from the baby 1900X through to the monstrosity that is the 1950X.
This means the same 64 PCIe lane allocation from top to bottom, support for high-density quad-channel memory and high core counts across the board, ranging from 8 (1900X) to 16 (1950X) with doubled thread counts, creating a truly functional HEDT system, can be done without adjusting for resource allocation compromises. For example, a system spec can be created that features a 4-way GPU solution, multiple M.2 NVMe SSDs in RAID, USB3.0 and 3.1 support, numerous SATA HDDs, and other related resources that utilise PCIe lane allocation without adjustments due to, for example, M.2 slots removing SATA, USB or PCIe slot functionality.
RAMMING THE POINT HOME
Ryzen 7 had some RAM teething issues as the market adjusted away from an almost singular focus on Intel. These issues were tirelessly worked on by AMD’s performance engineers and solutions flooded through in the weeks leading up to and following the Ryzen 7 release. Now, with the Threadripper launch, the CPU review kits were bundled with G.Skill Trident-Z RGB DDR4-3200 C14 4 x 8GB kits to seemingly prove a point. And they did. The platform runs effortlessly with 32GB of quad-channel memory operating at DDR4-3200 14-14-14-34 and at a tight 1T command rate — well done!