LG’s UltraGear 27GX790B-B is a real 27-inch-class OLED gaming monitor, but its headline specification needs one important qualification: it runs at 540Hz in 2,560 × 1,440, or at 720Hz only when the resolution is reduced to 1,280 × 720. It is not a 1440p 720Hz monitor.
Announced for the U.S. on January 6, 2026, the monitor combines LG’s fourth-generation Tandem OLED panel with DisplayPort 2.1, a rated 0.02ms GtG response time, and both NVIDIA G-SYNC Compatible and AMD FreeSync Premium Pro support. Its appeal is strongest for competitive players with hardware capable of producing extremely high frame rates.
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LG 27GX790B-B: the important specifications
| Specification | LG UltraGear 27GX790B-B |
|---|---|
| Screen size | 27-inch class; some regional documents list a 26.5-inch panel |
| Panel | Fourth-generation Tandem OLED / Primary RGB Tandem OLED |
| QHD mode | 2,560 × 1,440 at up to 540Hz |
| HD mode | 1,280 × 720 at up to 720Hz |
| Response time | 0.02ms GtG, rated by LG |
| HDR | VESA DisplayHDR True Black 500 |
| Motion certification | VESA ClearMR 21000 |
| Adaptive sync | NVIDIA G-SYNC Compatible and AMD FreeSync Premium Pro |
| Connectivity | DisplayPort 2.1, HDMI 2.1, USB and headphone connectivity; confirm regional specifications before buying |
| U.S. warranty | Two years for labor and two years for parts, according to LG’s support listing |
LG’s official product page describes the display as a “27 Inch UltraGear OLED Dual Mode QHD 540Hz or HD 720Hz” monitor. That wording is more precise than simply calling it a 720Hz 1440p display.
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The monitor has two distinct operating modes:
- 2,560 × 1,440 at 540Hz: the normal high-resolution gaming mode.
- 1,280 × 720 at 720Hz: the specialized esports mode.
At 540Hz, a new frame can be displayed approximately every 1.85 milliseconds. At 720Hz, that interval falls to approximately 1.39ms. For comparison, 240Hz corresponds to about 4.17ms per frame.
#1 Best Overall
- LG UltraGear OLED Goes Glossy - Experience ultra-smooth, tear-free gameplay with up to 240Hz refresh rate and 0.03ms response time on a glossy, bright 27” QHD OLED display. React instantly, spot every detail, and outpace your opponents in every frame with outrageous speed and clarity.
- Next-Level OLED Brightness, for Next-Level Play - The brilliant OLED display brings every scene to life with jaw-dropping color and intensity. Delivering a standard 275 nits of brightness and peaking at 1300 nits, your games shine with vivid clarity—keeping dark corners detailed, explosions dazzling, and the action always visible no matter the environment.
- VESA DisplayHDR True Black 400 - An OLED display with VESA DisplayHDR True Black 400 and a 1.5M:1 contrast ratio deliver deep blacks and dazzling highlights, so you catch every hidden detail in dark scenes and every spark in the bright ones. With up to 98.5% DCI-P3 color, your worlds burst with vibrant intensity—making every game feel more alive.
- Three UL Certifications. One Clear Advantage for Eye Comfort. - This UltraGear OLED display is three times UL-certified—for Anti-Glare, Flicker-Free, and Low Blue Light. Combined with a glossy finish, the display helps reduce distractions, keep your view crisp, and maintain visual comfort—so you can stay focused and perform at your best, even during extended gaming sessions.
- 27” OLED Brilliance with up to 240Hz of Game-Changing Speed - Experience ultra-smooth, tear-free gameplay with up to 240Hz refresh rate on a glossy, bright 27” QHD OLED display.
That difference can matter in fast competitive games when the computer can actually render hundreds of frames per second and the player is sensitive to motion clarity and latency. It does not make every game dramatically more responsive, however. A system producing 180 frames per second cannot take full advantage of a 540Hz or 720Hz panel, and network latency, CPU performance, input devices and game-engine limits can remain larger constraints.
The cost of the 720Hz setting is image detail. At 27 inches, 1,280 × 720 is visibly much softer than 2,560 × 1,440. The mode is therefore aimed at players who deliberately prioritize maximum frame rate over sharpness in games such as competitive shooters—not at users seeking the best image quality in every title.
What Tandem OLED changes
The 27GX790B-B uses LG’s fourth-generation Primary RGB Tandem OLED panel design. Tandem OLED uses multiple emissive OLED layers rather than the structure used by a conventional single-layer OLED panel.
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1Clear out junk files and repair common Windows errors2Scan for outdated or missing drivers - takes under a minute3Repair Windows errors before they cause bigger problemsLG positions the design as improving light efficiency, brightness potential, color performance and panel longevity while reducing power consumption compared with older OLED structures. LG also presented the monitor as its brightest OLED gaming monitor at launch and specifies DisplayHDR True Black 500.
Those statements should be understood as manufacturer positioning and certification details, not as independent measurements of sustained brightness, input lag or long-term durability. Tandem OLED does not make the panel burn-in-proof. Static taskbars, desktop windows and game HUDs can still create image-retention risks, so buyers should use the monitor’s panel-care features and avoid treating it like an always-on static office display.
Rank #2
- World's First 5K2K OLED Gaming Monitor - Gaming like never before with the world's first 5K2K WUHD (5120 x 2160) resolution on a massive 45” curved OLED screen. This unparalleled clarity on an ultra-wide aspect ratio pulls you deep into the action, surrounding you with stunning visuals and astounding detail. Perfect for epic battles or cinematic adventures, this UltraGear is your window to ultimate gaming perfection.
- 125 PPI: Sharp Text Clarity with Reduced Color Fringe - Designed with an updated subpixel layout, the 5K2K UltraGear OLED screen reduces color fringing for sharper, clearer text. 125 pixels per inch (PPI) is perfect for both work and play: crisp text clarity paired with bold, vivid visuals.
- Bright 45" OLED Picture: Up to 1300 nits with Deep Blacks and Brilliant Color - Experience bright OLED visuals at up to 1300 nits peak brightness. With color up to 98.5% of DCI-P3 color coverage, a 1.5M:1 contrast ratio, and DisplayHDR True Black 400, every gaming scene pops with deep blacks, brilliant highlights, and cinematic color.
- Dual Mode: 5K2K 165Hz or WFHD at 330Hz - Dual Mode lets you take control of your gaming experience. Enjoy graphically stunning story-driven adventures in 5K/WUHD at up to 165Hz, immersing yourself in epic visuals and rich detail. Or press the hotkey to switch to Wide Full HD at an electrifying 330Hz for ultra-responsive gameplay in FPS, MOBA, or racing titles.
- 0.03ms (GtG): Astounding OLED Speed - Play with a near-instantaneous 0.03ms response time, which minimizes ghosting for gaming visuals that are sharp, clear and buttery smooth.
LG Display separately described the underlying 27-inch 540Hz/720Hz OLED panel as a fourth-generation Tandem OLED design and said it received a 2026 Society for Information Display “Display of the Year” award. That is panel-level recognition, not an independent review of the finished 27GX790B-B retail monitor. LG Display’s announcement provides the company’s account of that award.
Why DisplayPort 2.1 matters—and what it does not prove
DisplayPort 2.1 is an appropriate connection for a monitor offering extremely high refresh rates. LG says it provides the bandwidth needed for the display’s high-refresh operation. The monitor also includes HDMI 2.1.
However, “DisplayPort 2.1” alone does not establish the connector’s exact UHBR speed or whether a particular mode uses Display Stream Compression. Buyers should not assume that every DisplayPort 2.1 product provides the maximum possible 80Gbps UHBR20 link. LG’s U.S. product material confirms DisplayPort 2.1, but the supplied specifications do not establish a full-bandwidth UHBR20 implementation.
The graphics card, cable, driver and selected resolution all matter. LG also notes that the available refresh rate depends on the computer’s specifications and configuration.
PC requirements and setup realities
The monitor cannot create 540 or 720 frames per second by itself. To benefit from its headline modes, a buyer needs:
Rank #3
- 240Hz Refresh Rate - Gear up for smooth gameplay with an ultra-fast 240Hz OLED display. The faster speed lets you respond quickly to opponents and stay a step ahead of the competition. Plus, enjoy smoother scenes with less lag or ghosting thanks to LG UltraGear OLED's nearly instantaneous 0.03ms (GtG) response time.
- VESA DisplayHDR True Black 400 & 1.5M:1 contrast ratio - VESA DisplayHDR True Black 400 certified means this monitor meets industry standards for brightness as well as deep, rich black color expression. With a 1.5M:1 contrast ration, the benefit for gaming impeccable color and image detail in dark scenes for a stunning visual experience.
- NVIDIA G-SYNC Compatible and AMD FreeSync Premium Pro - Officially validated by NVIDIA as G-SYNC Compatible and equipped with AMD FreeSync Premium Pro means this UltraGear provides smooth, fast action that reduces screen tearing and stutter. Never miss a frame of the action as you clinch your victories.
- Anti-Glare / Low Reflection OLED - Play with less distractions thanks to an anti-glare screen that minimizes light reflections and lets you concentrate on winning.
- 2 Year UltraGear OLED Warranty - Game with peace of mind. This UltraGear OLED gaming monitor is protected by a two year limited warranty covering internal and functional parts and labor, including OLED Display Panel. See Warranty Information on this page for all warranty details.
- A GPU capable of rendering the chosen game at the selected resolution and frame rate.
- A sufficiently fast CPU, particularly in esports titles that become CPU-limited at very high frame rates.
- A suitable DisplayPort 2.1-capable output, cable and port configuration where required.
- Current graphics drivers and a correctly selected refresh rate in Windows and the game.
- A game engine and graphics preset that can scale to very high frame rates.
For 540Hz or 720Hz play, competitive settings may require reduced effects, lower render scale, disabled ray tracing and other image-quality compromises. If the system cannot sustain the target frame rate, the monitor can still be used at a lower refresh rate, but the premium is harder to justify.
LG states that G-SYNC Compatible support works with GeForce GTX 10-series and newer graphics cards over DisplayPort, while its HDMI 2.1 compatibility note lists GeForce RTX 30-series and newer GPUs. These are LG’s stated compatibility conditions and should not be treated as a guarantee for every system configuration.
How it compares with the LG 27GX790A-B
The model suffix matters. The older 27GX790A-B is a 1440p/480Hz WOLED monitor. The newer 27GX790B-B uses the Tandem OLED design, raises the QHD refresh rate to 540Hz and adds the 720p/720Hz mode.
| Feature | 27GX790A-B | 27GX790B-B |
|---|---|---|
| Panel generation | Earlier WOLED design | Fourth-generation Tandem OLED |
| Maximum QHD refresh rate | 480Hz | 540Hz |
| 720Hz mode | Not identified in official launch material | 720Hz at 1,280 × 720 |
| Rated response time | 0.03ms GtG | 0.02ms GtG |
| HDR certification | VESA DisplayHDR True Black 400 | VESA DisplayHDR True Black 500 |
| DisplayPort | DisplayPort 2.1 | DisplayPort 2.1 |
The B model is not merely the same monitor with a slightly higher refresh rate. Its panel generation, HDR certification and dual-mode operation are central differences. The A model may still make sense if it is substantially cheaper and 480Hz at 1440p is sufficient.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Price and U.S. availability
LG announced a U.S. launch price of $999.99 on January 6, 2026. Later LG listing pages showed promotional prices between $699.99 and $729.99, but those are time-sensitive snapshots rather than a stable price. Check the current LG product page immediately before buying.
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Rank #4
- Dual Mode: 4K UHD 240Hz or Full HD 480Hz - LG UltraGear OLED is a VESA Certified Dual Mode gaming monitor. This innovation allows gamers to experience graphically rich, story-driven games in 4K/UHD at up to 240Hz or switch to Full HD at up to 480Hz for fast-paced FPS, MOBA or racing games via hotkey.
- Leave Lag Behind with 0.03ms Response Time - Enjoy smoother scenes with less lag or ghosting thanks to LG UltraGear OLED's nearly instantaneous 0.03ms (GtG) response time.
- NVIDIA G-SYNC Compatible and AMD FreeSync Premium Pro - Officially validated by NVIDIA as G-SYNC Compatible and equipped with AMD FreeSync Premium Pro means this UltraGear provides smooth, fast action that reduces screen tearing and stutter. Never miss a frame of the action as you clinch your victories.
- Bright OLED Gaming - This UltraGear features Micro Lens Array+ technology. So with a typical brightness of 275 nits and a peak brightness of up to 1300 nits, this monitor is UltraGear's brightest OLED gaming display.
- VESA DisplayHDR True Black 400 & 1.5M:1 Contrast Ratio - VESA DisplayHDR True Black 400 certified means this monitor meets industry standards for brightness as well as deep, rich black color expression. With a 1.5M:1 contrast ration, the benefit for gaming impeccable color and image detail in dark scenes for a stunning visual experience.
LG’s launch promotion included a free 27-inch FHD 240Hz monitor for qualifying pre-orders through February 1, 2026. That offer was historical and should not be treated as active unless LG announces a replacement promotion.
Warranty and included accessories can differ by market. Before ordering, confirm the regional model suffix, cable selection, warranty terms, HDR specification and retailer availability. LG’s U.S. support listing gives the 27GX790B-B two years of labor and two years of parts coverage, but buyers should review the full warranty terms rather than assume all OLED image retention is covered.
Who should buy the 27GX790B-B?
This monitor is a strong fit for:
- Competitive FPS players and esports-focused users.
- Players with high-end PCs that can sustain very high frame rates.
- Buyers who want 1440p for ordinary gaming but a dedicated lower-resolution mode for competitive play.
- Users who value OLED contrast and near-instant pixel response.
- Enthusiasts willing to pay for a specialized performance feature rather than a general-purpose display.
Who should skip it?
It is a poor fit for buyers who:
- Primarily play cinematic AAA games that cannot approach 540 or 720 frames per second.
- Need 4K resolution or USB-C laptop docking.
- Use a midrange PC that cannot drive the monitor at high refresh rates.
- Spend most of the day viewing static productivity applications.
- Do not want to manage OLED panel-care features or accept possible image-retention risk.
- Expect 720Hz at 2,560 × 1,440.
Common problems and what to check
720Hz is not available
First confirm that the monitor is using its 720p mode rather than 1440p/540Hz. Then check the GPU output, cable, driver and Windows advanced display settings. A game’s internal frame-rate counter does not prove that the display is operating at 720Hz. Verify the active mode in the monitor’s information display and the operating system.
The 720Hz mode looks too soft
That is expected: the mode is 1,280 × 720. Use 720Hz only in games where motion speed and maximum frame rate matter more than image detail, and switch back to 1440p/540Hz for general gaming and desktop use.
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Lower graphical settings, disable demanding ray-tracing effects, reduce render scale and check whether the CPU is the limiting component. Do not treat the maximum refresh rate as a guaranteed frame-rate target.
Verdict
The LG 27GX790B-B is best understood as a flexible 1440p/540Hz Tandem OLED monitor with a specialized 720p/720Hz esports mode. That makes it more versatile than a fixed 1440p/480Hz display for high-end competitive players, but the headline 720Hz number should not be mistaken for a free upgrade in resolution and speed at the same time.
For the right buyer—someone with a powerful PC, competitive games and a genuine preference for maximum motion performance—the dual-mode design is compelling. For mixed gaming, productivity or image-quality-first use, a less expensive 240Hz or 360Hz OLED, or a conventional high-refresh LCD, may deliver better value.
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