Asus ROG Zephyrus Duo 15 GX550 review: Two screens and a whole lot of speed

This tilting dual-screen gaming laptop packs liquid metal, Core i9-10980HK, and GeForce RTX 2080 Super

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ROG Zephyrus Duo Testing

For performance testing Asus recommends using the Armoury Crate utility to switch from its default setting of Performance to Turbo. We actually tested both, as many people never ever switch out of default mode.

The ROG Zephyrus Duo is the first laptop we’ve tested that has been confirmed to have Nvidia’s Dynamic Boost features. Dynamic Boost is supposed to shift power intelligently between the CPU and GPU based on the gaming load. If, for example, a game is heavy on graphics (and most are), the GPU will ramp up while the CPU will ramp down. If a game is dependent on CPU, it should ramp up while the GPU ramps down.

zephyrus 3 Gordon Mah Ung

ROG Zephyrus Duo 15 CPU Performance

Our first benchmark is Maxon’s Cinebench R15, which measures a CPU’s performance rendering a 3D model. It’s nearly a pure CPU load, and more cores are better.

The result is actually spectacular when you compare it to the other top Intel-based laptops. The ROG Zephyrus Duo sticks close to them despite being almost a third lighter and half the bulk too. We’re seeing performance a little faster than the Acer Predator Helios 700, which weighs 10 pounds and features a slide keyboard to improve airflow.

The better comparison is against other 8-core thin and light gaming and work laptops, which are left eating the dust of the ROG Zephyrus Duo. 

And yes, we will point out just how impressive the Ryzen 9 4900HS is in the ROG Zephyrus 14.

asus zephyrus duo cinebench r15 nt IDG

To measure how the Zephyrus Duo performs in lighter tasks, we use Cinebench R15 again, but set to use a single thread. As is often the case with this test, it’s mostly a tie. You’d likely never tell the difference in daily use between the number-10 laptop on this list and the number 1. If all you care about is single-threaded performance for daily use—these are all equally good.

asus zephyrus duo cinebench r15 1t IDG

Our next test stresses the CPU for a longer period to see how it handles itself as it gets hot. We take a 30GB file and encode it using to Android TV preset, using an older version of the free HandBrake utility. The test used to take in excess of 45 minutes when we first adopted it four years ago, but we’re down to basically 20 minutes with modern laptops.

Here, we see the Asus ROG Zephyrus Duo perform in the neighborhood of laptops almost twice its weight. It’s almost 10 percent faster than the MSI GS66 Stealth which features the same CPU. The GS66 is about a pound lighter, but both are definitely in the same neighborhood versus the 11-pound Acer Predator Helios 700. That leading Alienware Area 51m R1 actually features a desktop Core i9-9900K. 

asus zephyrus duo handbrake IDG

Zephyrus Duo 15 Gaming Performance

Moving to graphics performance, we’ll kick this off with UL’s 3DMark Time Spy, a synthetic benchmark that lets us separate pure graphics performance from CPU performance. Games are always useful for gut checks, but for a repeatable and accurate test, 3DMark is hard to beat.

One pattern we’ve noticed with recent thin-and-light gaming laptops is the importance of thermal management. The default performance can be pretty similar, but they start to differentiate when run in their “Turbo,” “Extreme,” or whatever high-octane performance profile the laptop maker offers. In that setting, the ROG Zephyrus Duo doesvery well. The 8-pound Alienware Area 51M R1 and the 11-pound Predator Helios 700 heavily flex their muscles here because they simply have much larger bodies to pack in more cooling and power delivery.

asus zephyrus duo 3dmark time spy graphics IDG

The ROG Zephyrus Duo does slightly underperform in default mode, but Time Spy is somewhat of a lighter load today and we suspect that to be the issue (which we’ll discuss later).

We wanted to try something more forward-looking so we also run 3DMark’s Port Royal, which measures Ray Tracing Performance. On its default setting the ROG Zephyrus Duo is essentially dead-even with the thinner and lighter MSI GS66 Stealth. That’s no surprise, as both laptops on default are held to their factory limits on the graphics cards. 

Set the Zephyrus Duo to its Turbo setting, though, and we see almost a 16-percent improvement in the Port Royal score.

asus zephyrus duo port royal IDG

3DMark’s Port Royal only measures ray tracing performance in reflections and shadows. For a view into the future, we ran the fully path traced version of Quake II RTX, which reinvigorates the 23-year-old game with future looking graphics.

In Quake II RTX we also see a fairly compressed finish between all of the gaming laptops here, which we expected. Even though it’s a 23-year-old game, the techniques it uses are simply brutal. That green bar on top is when the ROG Zephyrus Duo is on its Turbo setting and the GPU—for the most part—is allowed to run more freely. The result is about a 16-percent improvement in performance.

asus zephyrus duo quake ii rtx IDG

We also ran the challenging Red Dead Redemption 2, with the ROG Zephyrus Duo set to 1920x1080 and balanced graphics. We saw 77 fps out of it on its stock setting and an 8.5-percent increase in performance by switching to the Turbo mode. Basically most heavy-duty graphics and gaming loads and moderately heavy go like hell on the ROG Zephyrus Duo. 

But we still run older games, and that’s where we hit a snag. Running the seven-year-old Rise of the Tomb Raider we expected performance to be stellar, but we confusingly saw frame rates closer to that of a system with a GeForce GTX 1660 Ti.

asus zephyrus duo rise of the tomb raider IDG

We tried running the benchmark with the second panel switched off and double-checked that our unit was on AC, but we could not resolve our issue. Looking through recorded numbers for the extremely lightweight 3DMark Sky Diver test we also saw unexplained weirdness.

This shouldn't be happening. Below you can see the performance of the MSI GS66 set to its default “Balanced” and its “Extreme” setting. You can also see XPG’s Xenia 15, which we’re in the process of reviewing. It features a hardware button to swap among a Power Saver Mode, a Balanced Mode, and a Performance mode. Like the MSI, the XPG laptop performance is where we expected, but with a bigger boost from Balanced to Performance as it’s slightly thicker and isn’t quite as thermally limited by its parts. 

light load weirdness IDG

We think early algorithms are to blame for just odd performance from the Zephyrus Duo in very light test loads.

The XPG Xenia 15, when set to its Power Saver mode, locks down the CPU and GPU clock speeds and power consumption to extend battery life. All this is expected.

The ROG Zephyrus Duo, however, just gets plain weird. Again, we see far substandard graphics and CPU performance. The bizarre swing going from its default Performance to Turbo just makes no sense.

Like most 3DMark tests, Sky Diver will first run two graphics tests intended to measure the GPU. Then it will run a simulated game physics test to measure CPU performance. 3DMark is reporting that moments after the physics test is kicked off, the CPU will spike up above 4GHz, and then dive down to 2.5GHz for a while before climbing back out of the valley.

While you might think this is just our unit, the truly blistering performance everywhere else makes us think it isn’t. What’s the issue? Nvidia’s Dynamic Boost or Asus’ own algorithm? We won’t know, but we are continuing to work with Asus to resolve it. We’re 90 percent sure this is nothing more than the result of the early algorithms and can be addressed in future updates.

ROG Zephyrus Duo Battery Life

Our last test is battery life. For that we loop a 4K video using Windows 10's super-efficient Movies & TV player. We put the laptop into airplane mode, with its display set at 250 to 260 nits. We also plug in a set of earbuds to try to reduce the impact of the audio subsystem on results. 

The ROG Zephyrus Duo will automatically kick down to Silent mode when on battery to conserve power, but it does not turn off the second screen. Because most people will switch off the second panel to watch a movie on a trip, we turned it off as well (a button just above the trackpad lets you easily do this).

The result was a respectable six-plus hours off its 90-watt-hour battery. Both the MSI GS66 Stealth and Gigabyte’s Aero 17 get closer to 7 hours, but that’s not a huge difference like you’d see with, say, Dell’s new XPS 15 9500, which hammers out more than 10 hours.

We also ran the same video test with the second screen turned on, but dimmed considerably. We saw about 4 hours of battery life.

Keep in mind that our video test, while realistic, can be considered a light test. Switch on the Wi-Fi and browse the web or run Office, and you can expect to take a third or more off battery life. Fire up a video editor or game, and you can expect no more than an hour or two, realistically. 

Basically, battery life seems mostly in line with a gaming laptop experience, unless you run both screens at once.

asus zephyrus duo video run down test IDG

Conclusion

There’s a lot to unpack with the ROG Zephyrus Duo, but we’ll start with the performance. If you believe us that the subpar performance on light gaming tasks is probably a temporary issue, the takeaway is that it’s very fast for its weight and stature. We suspect as we see another three or five 15-inch laptops with similar part combinations, most will settle down closer to the Gigabyte Aero 17 or MSI GS66 Stealth in performance. Asus’ use of liquid metal and better cooling paths simply makes it the laptop to beat, and we’re not sure others in the same class of laptop can do that.

The second point we want to touch on is the price. As configured, our review unit pushes $3,699 on Asus.com. That’s practically Apple pricing (except you’re getting a boatload more performance and features), but gaming laptops are not getting cheaper. The far more conventional MSI GS66 Stealth, with a 300Hz panel and mostly similar parts, is $3,000. The Gigabyte Aero 17, with an arguably better 10-bit, HDR 400 4K screen, plus an 8-core Core i7-108750H, GeForce RTX 2070 Super, and half the RAM and far less storage, is $2,700.

The decision comes down to how much value that second screen adds. That’s very much a personal choice, but we have to say as multi-monitor users we find it invaluable. Whether it’s to view reference documents while editing in the main window, watching a video while working, or monitoring the team statistics of the players you’re facing in a match, we could never go back to a single screen on our desktop. With Asus’ ROG Zephyrus Duo 15 GX550, now you don’t have to do it with a laptop, either.

zephyrus 4 Gordon Mah Ung

This story, "Asus ROG Zephyrus Duo 15 GX550 review: Two screens and a whole lot of speed" was originally published by PCWorld.

At a Glance
  • The Asus ROG Zephyrus Duo 15 GX550 is a dual-screen laptop that gets it right. From the sturdy tilting mechanism to the strong performance, it's a great package , though it comes at a price.

    Pros

    • A tilt-out second screen!
    • Top-of-the-line performance

    Cons

    • Very expensive because of the second screen
    • Puzzling performance on low-intensity gaming
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