Hardware Guides

Vega’s partnership with the Samsung CF791, prior to the card even launching, was met with unrelenting criticism of the monitor’s placement in bundles. Consumer reports on the monitor mention flickering with Ultimate Engine as far back as January, now leveraged as a counter to the CF791’s inclusion in AMD’s bundle. All these consumer reports and complaints largely hinged on Polaris or Fiji products, not Vega (which didn’t exist yet), so we thought it’d be worth a revisit with the bundled card. Besides, if it’s the bundle of the CF791 with Vega that caused the resurgence in flickering concerns, it seems that we should test the CF791 with Vega. That’s the most relevant comparison.

And so we did: Using Vega 56, Vega: FE, and an RX 580 Gaming X (Polaris refresh), we tested Samsung’s CF791 34” UltraWide display, running through permutations of FreeSync. Some such permutations include “Standard Engine” (OSD), “Ultimate Engine” (OSD), and simple on/off toggles (drivers + OSD).

As exciting as it is to see “+242% power offset” in overclocking tools, it’s equally deflating to see that offset only partly work. It does, though, and so we’ve minimally managed to increase our overclocking headroom from the stock +50% offset. The liquid cooler helps, considering we attached a 360mm radiator, two Corsair 120mm maglev fans, a Noctua NF-F12 fan, and a fourth fan for VRM cooling. Individual heatsinks were also added to hotter VRM components, leaving two sets unsinked, but cooled heavily with direct airflow.

This mod is our coolest-running hybrid mod yet, with large thanks to the 360mm radiator. There’s reason for that, too – we’re now able to push peak power of about 370-380W through the card, up from our previous limitation of ~308W. We were gunning for 400W, but it’s just not happening right now. We’re still working on BIOS mods and powerplay table mods.

Following an initial look at thermal compound spread on AMD’s Threadripper 1950X, we immediately revisited an old, retired discussion: Thermal paste application methods and which one is “best” for a larger IHS. With most of the relatively small CPUs, like the desktop-grade Intel and AMD CPUs, it’s more or less been determined that there’s no real, appreciable difference in application methods. Sure – you might get one degree Centigrade here or there, but the vast majority of users will be just fine with the “blob” method. As long as there’s enough compound, it’ll spread fairly evenly across Intel i3/i5/i7 non-HEDT CPUs and across Ryzen or FX CPUs.

Threadripper feels different: It’s huge, with the top of the IHS measuring at 68x51mm, and significantly wider on one axis. Threadripper also has a unique arrangement of silicon, with four “dies” spread across the substrate. AMD has told us that only two of the dies are active and that it should be the same two on every Threadripper CPU, with the other two being branded “silicon substrate interposers.” Speaking with Der8auer, we believe there may be more to this story than what we’re told. Der8auer is investigating further and will be posting coverage on his own channel as he learns more.

Anyway, we’re interested in how different thermal compound spreading methods may benefit Threadripper specifically. Testing will focus on the “blob” method, X-pattern, parallel lines pattern, Asetek’s stock pattern, and AMD’s recommended five-point pattern. Threadripper’s die layout looks like this, for a visual aid:

amd threadripper grid

Because of the spacing centrally, we are most concerned about covering the two clusters of dies, not the center of the IHS; that said, it’s still a good idea to cover the center as that is where the cooler’s copper density is located and most efficient.

Our video version of this content uses a sheet of Plexiglass to illustrate how compound spreads as it is applied. As we state later in the video, this is a nice, easy mode of visualization, but not really an accurate way to show how the compound spreads when under the real mounting force of a socketed cooler. For that, we later applied the same NZXT Kraken X62 cooler with each method, then took photos to show before/after cooler installation. Thermal testing was also performed. Seeing as AMD has permitted several other outlets to post their thermal results already, we figured we'd add ours to the growing pool of testing.

Modern humans used to hang undesirables in the town square and light “witches” aflame. For lack of a witch, PC hardware enthusiasts prefer to seek out companies that other internet users have suggested as wrongdoers. Legitimate or not, the requirement to stop and think about something need not apply here – we need more rage for the combustion engine; this thing doesn’t run on neutrality.

Posting a concern about a product, like Reddit user Kendalf did, cannot be praised enough. This type of alert gets attention from manufacturers and media alike, and means that we can all work together to determine if, (1) there is actually an issue, and (2) how we can fix it or work around it. The result is stronger products, hopefully. As stated in the lengthy conclusion below, though, it’s an unfortunate side effect that other commenters then elect to blow things out of proportion for need to feel upset about something. There’s always room for a one-off defect, for misunderstandings of features, or just a bad batch. There’s also room for a manufacturer to really screw up, so it just depends on the situation. Ideally, the mobs remain at bay until numerous people have actually verified something.

 

We took time aside at AMD’s Threadripper & Vega event to speak with leading architects and engineers at the company, including Corporate Fellow Mike Mantor. The conversation eventually became one that we figured we’d film, as we delved deeper into discussion on small primitive discarding and methods to cull unnecessary triangles from the pipeline. Some of the discussion is generic – rules and concepts applied to rendering overall – while some gets more specific to Vega’s architecture.

The interview was sparked from talk about Vega’s primitive shader (or “prim shader”), draw-stream binning rasterization (DSBR), and small primitive discarding. We’ve transcribed large portions of the first half below, leaving the rest in video format. GN’s Andrew Coleman used Unreal Engine and Blender to demonstrate key concepts as Mantor explained them, so we’d encourage watching the video to better conceptualize the more abstract elements of the conversation.

Our recent R7 1700 vs. i7-7700K streaming benchmarks came out in favor of the 1700, as the greater core count made it far easier to handle the simultaneous demands of streaming and gameplay without any overclocking or fiddling with process priority. Streaming isn’t the whole story, of course, and there are many situations (i.e. plain old gaming) where speed is a more valuable resource than sheer number of threads, as seen in our original 1700 review.

Today, we’re testing the R7 1700 and i7-7700K at 1440p 144Hz. We know the i7-7700K is a leader in gaming performance from our earlier CPU-bottlenecked 1080p testing; that isn’t the point here. We’ve also pitted these chips against each other in VR testing, where our conclusion was that GPU choice mattered far more, since both CPUs can deliver 90FPS equally well (and were effectively identical). This newest test is less of a competition and more of a “can the 1700 do it too” scenario. The 1700 has features that make it attractive for casual streaming or rendering, but that doesn’t mean customers want to sacrifice smooth 144Hz in pure gaming scenarios. As we explain thoroughly in the below video, there are different uses for different CPUs; it’s not quite as simple as “that one’s better,” and more accurately boils down to “that one’s better for this specific task, provided said task is your biggest focus.” Maybe that’s the R7 1700 for streaming while gaming, maybe that’s the 7700K for gaming -- but what we haven’t tested is if the 1700 can keep up at 144Hz with higher quality settings. We put to test media statements (including our own) that the 1700 should be “better at streaming,” finding that it is. It is now time to put to test the statements that the 7700K is “better at 144Hz” gaming.

This series is an ongoing venture in our follow-up tests to illustrate that, yes, the two CPUs can both exist side-by-side and can be good at different things. There’s no shame in being a leader in one aspect but not the other, and it’s just generally impossible given current manufacturing and engineering limitations, anyway. The 7700K was the challenger in the streaming benchmarks, and today it will be challenged by the inbound R7 1700 for 144Hz gaming.

People like to make things a bloodbath, but just again to remind everyone: This is less of a “versus” scenario and more of a “can they both do it?” scenario.

X299 VRM thermals have been a topic of interest in the lab lately, as we’ve continued to learn how to work with our new power testing tools and have fully revamped CPU thermal testing. The time will come eventually, but for now, we’ve worked with Buildzoid to run some calculations on VRM thermals with the Gigabyte X299 Gaming 9 motherboard. These numbers are based off of GN testing for this video, where we overclocked the CPU to 4.5~4.6GHz and checked for power consumption at the 8-pin headers (of which there are two).

The Gigabyte X299 Gaming 9 motherboard makes some interesting choices with its VRM components, ultimately balancing between “ridiculous overkill,” to quote Buildzoid, and merely adequacy. The board is one of the higher quality motherboards out there right now, and so is worth a watch on the PCB break-down:

“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.

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.

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