The right angle
While many in the media and enthusiast communities are still trying to fully grasp the importance and impact of the recent AMD Ryzen 7 processor release, I have been trying to complete my review of the 1700X and 1700 processors, in between testing the upcoming GeForce GTX 1080 Ti and preparing for more hardware to show up at the offices very soon. There is still much to learn and understand about the first new architecture from AMD in nearly a decade, including analysis of the memory hierarchy, power consumption, overclocking, gaming performance, etc.
During my Ryzen 7 1700 testing, I went through some overclocking evaluation and thought the results might be worth sharing earlier than later. This quick article is just a preview of what we are working on so don’t expect to find the answers to Ryzen power management here, only a recounting of how I was able to get stellar performance from the lowest priced Ryzen part on the market today.
The system specifications for this overclocking test were identical to our original Ryzen 7 processor review.
|Test System Setup|
|CPU||AMD Ryzen 7 1800X
AMD Ryzen 7 1700X
AMD Ryzen 7 1700
Intel Core i7-7700K
Intel Core i5-7600K
Intel Core i7-6700K
Intel Core i7-6950X
Intel Core i7-6900K
Intel Core i7-6800K
|Motherboard||ASUS Crosshair VI Hero (Ryzen)
ASUS Prime Z270-A (Kaby Lake, Skylake)
ASUS X99-Deluxe II (Broadwell-E)
|Storage||Corsair Force GS 240 SSD|
|Graphics Card||NVIDIA GeForce GTX 1080 8GB|
|Graphics Drivers||NVIDIA 378.49|
|Power Supply||Corsair HX1000|
|Operating System||Windows 10 Pro x64|
Of note is that I am still utilizing the Noctua U12S cooler that AMD provided for our initial testing – all of the overclocking and temperature reporting in this story is air cooled.
First, let’s start with the motherboard. All of this testing was done on the ASUS Crosshair VI Hero with the latest 5704 BIOS installed. As I began to discover the different overclocking capabilities (BCLK adjustment, multipliers, voltage) I came across one of the ASUS presets. These presets offer pre-defined collections of settings that ASUS feels will offer simple overclocking capabilities. An option for higher BCLK existed but the one that caught my eye was straight forward – 4.0 GHz.
With the Ryzen 1700 installed, I thought I would give it a shot. Keep in mind that this processor has a base clock of 3.0 GHz, a rated maximum boost clock of 3.7 GHz, and is the only 65-watt TDP variant of the three Ryzen 7 processors released last week. Because of that, I didn’t expect the overclocking capability for it to match what the 1700X and 1800X could offer. Based on previous processor experience, when a chip is binned at a lower power draw than the rest of a family it will often have properties that make it disadvantageous for running at HIGHER power. Based on my results here, that doesn’t seem to the case.
By simply enabling that option in the ASUS UEFI and rebooting, our Ryzen 1700 processor was running at 4.0 GHz on all cores! For this piece, I won’t be going into the drudge and debate on what settings ASUS changed to get to this setting or if the voltages are overly aggressive – the point is that it just works out of the box.
What Makes Ryzen Tick
We have been exposed to details about the Zen architecture for the past several Hot Chips conventions as well as other points of information directly from AMD. Zen was a clean sheet design that borrowed some of the best features from the Bulldozer and Jaguar architectures, as well as integrating many new ideas that had not been executed in AMD processors before. The fusion of ideas from higher performance cores, lower power cores, and experience gained in APU/GPU design have all come together in a very impressive package that is the Ryzen CPU.
It is well known that AMD brought back Jim Keller to head the CPU group after the slow downward spiral that AMD entered in CPU design. While the Athlon 64 was a tremendous part for the time, the subsequent CPUs being offered by the company did not retain that leadership position. The original Phenom had problems right off the bat and could not compete well with Intel’s latest dual and quad cores. The Phenom II shored up their position a bit, but in the end could not keep pace with the products that Intel continued to introduce with their newly minted “tic-toc” cycle. Bulldozer had issues out of the gate and did not have performance numbers that were significantly greater than the previous generation “Thuban” 6 core Phenom II product, much less the latest Intel Sandy Bridge and Ivy Bridge products that it would compete with.
AMD attempted to stop the bleeding by iterating and evolving the Bulldozer architecture with Piledriver, Steamroller, and Excavator. The final products based on this design arc seemed to do fine for the markets they were aimed at, but certainly did not regain any marketshare with AMD’s shrinking desktop numbers. No matter what AMD did, the base architecture just could not overcome some of the basic properties that impeded strong IPC performance.
The primary goal of this new architecture is to increase IPC to a level consistent to what Intel has to offer. AMD aimed to increase IPC per clock by at least 40% over the previous Excavator core. This is a pretty aggressive goal considering where AMD was with the Bulldozer architecture that was focused on good multi-threaded performance and high clock speeds. AMD claims that it has in fact increased IPC by an impressive 54% from the previous Excavator based core. Not only has AMD seemingly hit its performance goals, but it exceeded them. AMD also plans on using the Zen architecture to power products from mobile products to the highest TDP parts offered.
The Zen Core
The basis for Ryzen are the CCX modules. These modules contain four Zen cores along with 8 MB of shared L3 cache. Each core has 64 KB of L1 I-cache and 32 KB of D-cache. There is a total of 512 KB of L2 cache. These caches are inclusive. The L3 cache acts as a victim cache which partially copies what is in L1 and L2 caches. AMD has improved the performance of their caches to a very large degree as compared to previous architectures. The arrangement here allows the individual cores to quickly snoop any changes in the caches of the others for shared workloads. So if a cache line is changed on one core, other cores requiring that data can quickly snoop into the shared L3 and read it. Doing this allows the CPU doing the actual work to not be interrupted by cache read requests from other cores.
Each core can handle two threads, but unlike Bulldozer has a single integer core. Bulldozer modules featured two integer units and a shared FPU/SIMD. Zen gets rid of CMT for good and we have a single integer and FPU units for each core. The core can address two threads by utilizing AMD’s version of SMT (symmetric multi-threading). There is a primary thread that gets higher priority while the second thread has to wait until resources are freed up. This works far better in the real world than in how I explained it as resources are constantly being shuffled about and the primary thread will not monopolize all resources within the core.