Every now and then, a content piece falls to the wayside and is archived indefinitely -- or just lost under a mountain of other content. That’s what happened with our AMD Ryzen pre-launch interview with Sam Naffziger, AMD Corporate Fellow, and Michael Clark, Chief Architect of Zen. We interviewed the two leading Zen architects at the Ryzen press event in February, had been placed under embargo for releasing the interview, and then we simply had too many other content pieces to make a push for this one.
The interview discusses topics of uOp cache on Ryzen CPUs, power optimizations, shadow tags, and victim cache. Parts of the interview have been transcribed below, though you’ll have to check the video for discussion on L1 writeback vs. writethrough cache designs and AMD’s shadow tags.
“Good for streaming” – a phrase almost universally attributed to the R7 series of Ryzen CPUs, like the R7 1700 ($270 currently), but with limited data-driven testing to definitively prove the theory. Along with most other folks in the industry, we supported Ryzen as a streamer-oriented platform in our reviews, but we based this assessment on an understanding of Ryzen’s performance in production workloads. Without actual game stream benchmarking, it was always a bit hazy just how the R7 1700 and the i7-7700K ($310 currently) would perform comparatively in game live-streaming.
This new benchmark looks at the AMD R7 1700 vs. Intel i7-7700K performance while streaming, including stream output/framerate, drop frames, streamer-side FPS, power consumption, and some brief thermal data. The goal is to determine not only whether one CPU is better than the other, but whether the difference is large enough to be potentially paradigm-shifting. The article explores all of this, though we’ve also got an embedded video below. If video is your preferred format, consider checking the article conclusion section for some additional thoughts.
Ask GN returns for its 54th episode – we’ve gotten more consistent than ever – to discuss Noctua fan manufacturing locations (China & Taiwan), thermal pads vs. thermal paste usage on MOSFETs, Vega 10-bit support, and a couple other items.
A few of the items from this week peer into GN’s behind-the-scenes workings, as several viewers and readers have been curious about our staff, whether we keep products, or why we “waste” GPUs by using them for things other than mining.
As always, timestamps below the embed.
This feature benchmark dives into one of the top requests we received from our Patreon backers: Undervolt Vega: Frontier Edition and determine its peak power/performance configuration. The test roped us in immediately, yielding performance uplift largely across the board from preliminary settings tuning. As we dug deeper, once past all the anomalous software issues, we managed to improve Vega: FE Air’s power available to the core, reduce power consumption relative to this, and improve performance in non-trivial ways.
Although power target and core voltage are somewhat tied at the hip, both being tools for overclocking, they don’t govern one another. Power target offset dictates how much additional power budget we’re willing to provide the GPU core (from the power supply) in order to stabilize its clock. GPU Vcore governs the voltage supplied, and will generally range from 900 to 1250mv on Vega: FE cards.
Vega’s native DPM configuration runs its final three states at 1440MHz, 1528MHz, and 1600MHz for the P-states, with DPM7 at 1600MHz/1200mv. This configuration is unsustainable in stock settings, as the core is both power-starved and thermally throttled (we’ll show this in a moment). The thermal limiter on Vega: FE is ~85C, at which point the power and clock will fluctuate hard to try and maintain control of the core temperature. The result is (1) spikey frequencies and frametime latencies, worsening perceived performance, and (2) reduced overall performance as frequency struggles to maintain even 1528MHz (let alone the advertised 1600MHz). To resolve for the thermal issue, we can either configure a more intelligent fan curve than AMD’s stock configuration or create a Hybrid card; unfortunately, we’re still left with a new problem – a power limit.
The power limit can be resolved in large part by offsetting power target by +50%. Making this modification is easy and “fixes” the issue of clock-dropping, but introduces (1) new thermal issues – resolvable by configuring a higher fan RPM, of course, and (2) absurdly high power consumption for a non-linear scaling in performance. In order to truly get value out of this approach, undervolting seems the next appropriate measure. AMD’s native core voltage is far higher than necessary for the card to operate at its 1600MHz target, and so lowering voltage improves performance from the out-of-box config. This is for thermal and power reasons alike. We ultimately see significantly reduced power consumption, to the tune of ~90W in some cases, a more stable core clock and thereby higher performance, and lower temperature – and thereby controllable noise.
We can’t get all the way down to the inner workings of the pump on this one, unfortunately, as all of our source images for the Vega: Frontier Edition – Watercooled card are from a reader. The reader was kind enough to remove the shroud from their new WC version of Vega: FE so that we could get an understanding of the basics, leading us to the conclusion that AMD has built one of the most expensive pre-built liquid cooling solutions for a graphics card.
The video tear-down goes into detail on the images we received, but we’ll revisit most of it here. The card uses the same base PCB, same VRM, same GPU/HBM layout and positioning, and same everything as the air-cooled card. The difference is entirely in the cooling solution, where the Delta VRM fan goes away and is replaced with an additional reservoir (more on that in a moment), while the GPU/VRM cooling is handled by liquid plates and a pump. The die-case finstack atop the I/O is also now gone, and the baseplate is simplified to an aluminum plate with no protrusions.
This week's hardware news recap gives us a break from Vega -- if a brief one -- so that we can discussed nVidia's multi-chip GPU white paper, AMD's Ryzen Threadripper CPUs (1920X + 1950X), the R3 CPUs, and new fabs for Samsung. This discussion also bleeds over into DRAM shortages and NAND prices, particularly relating to Micron's fab "event" from last week.
The show notes are below the embedded video, for folks who prefer the notes and sources.
Liquid-cooling the AMD Vega: Frontier Edition card has proven an educational experience for us, yielding new information about power leakage and solidifying beliefs of a power wall. We also learned that overclocking without thermal barriers (or thermal-induced power barriers) grants significant performance uplift in some scenarios, including gaming and production, though is done at the cost of ~33A from the PSU over 12V PSU power.
Our results for the AMD Vega: Frontier Edition liquid-cooling hybrid mod are in, and this review covers the overclocking scalability, power limits, thermal change, and more.
The Hybrid mod was detailed in build log form over in part 1 of the endeavor. This mod wasn’t as straight-forward as most, seeing as we didn’t have any 64x64mm brackets for securing the liquid cooler to the card. Drilling through an Intel mounting plate for an Asetek cooler, we were ultimately able to get an Asetek 570LC onto the card, which we later equipped with a Gentle Typhoon 120mm fan. VRM FET cooling was handled by aluminum finstacks secured by thermal adhesive, cooled with 1-2x Corsair ML120 fans. That said, this VRM cooling solution also wasn’t necessary – we could have operated with just the fans, and did at one point operate with just the heatsinks (and indirect airflow).
Specs and prices for AMD’s upcoming Ryzen Threadripper CPUs have been announced, as well as a general release date. The 12C/24T 1920X and 16C/32T 1950X will be available worldwide starting in “Early August,” with prebuilt Alienware systems available for preorder starting July 27th. According to AMD:
“Both are unlocked, use the new Socket TR4, have quad-channel DDR4, and feature 64 lanes of PCI Express. Base clock on the Ryzen Threadripper 1950X 16-core product is 3.4 GHz with precision boost to 4.0 GHz. On the Ryzen Threadripper 1920X 12-core product, the base clock is 3.5 GHz with precision boost to 4.0 GHz.”
As an aside, manufacturers informed GamersNexus at Computex that board release dates are targeted for August 10. It’s possible that this date has changed in the time since the show, but that seems to be the known target for Threadripper.
We’ve already endured one launch of questionable competence this quarter, looking at X299 and Intel’s KBL-X series, and we nearly escaped Q2 without another. Vega: Frontier Edition has its ups and downs – many of which we’ll discuss in a feature piece next week – but we’re still learning about its quirks. “Gaming Mode” and “Pro Mode” toggling is one of those quirks; leading into this article, it was our understanding – from both AMD representatives and from AMD marketing – that the switch would hold a relevant impact on performance. For this reason, we benchmarked for our review in the “appropriate” mode for each test: Professional applications used pro mode, like SPECviewperf and Blender. Gaming applications used, well, gaming mode. Easy enough, and we figured that was a necessary methodological step to ensure data accuracy to the card’s best abilities.
Turns out, there wasn’t much point.
A quick note, here: The immediate difference when switching to “Gaming Mode” is that WattMan, with all its bugginess, becomes available. Pro Mode does not support WattMan, though you can still overclock through third-party tools – and probably should, anyway, seeing as WattMan presently downclocks memory to Fury X speeds, as it seems to have some leftover code from the Fury X drivers.
That’s the big difference. Aside from WattMan, Gaming Mode technically also offers AMD Chill, something that Pro Mode doesn’t offer a button to use. Other than these interface changes, the implicit, hidden change would be an impact to gaming or to production performance.
Let’s briefly get into that.
This week's hardware news recap primarily focuses on industry topics, like new NAND from Toshiba, Western Digital, and a new SSD from Intel (first 64-layer VNAND SSD). A few other topics sneak in, like AMD's Ryzen Pro CPU line, a Vega reminder (in the video), the death of Lexar, and a few gaming peripherals.
Through the weekend, we'll be posting our Zotac 1080 Ti Amp Extreme review, the first part of our AMD Vega: Frontier Edition Hybrid mod, and a special benchmark feature in our highly acclaimed "Revisit" series.
In the meantime, here's the last week of HW news recapped:
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