I reviewed LG’s UltraGear 27GX790B-B, a 27-inch OLED gaming monitor and the first Primary RGB Tandem OLED I’ve had on the channel. The headline feature is the Dual Mode refresh rate: 1440p at a ridiculous 540Hz, or 720p at an even more absurd 720Hz—assuming your PC can actually push those frames. I cover the build, stand adjustability (including that it will pivot to portrait if you do it from the left side with a bit of strength), the full menu features, and the port selection—two HDMI 2.1 ports with VRR, DisplayPort 2.1 with full 80Gbps bandwidth, USB-C upstream with video passthrough, plus USB-A ports and a 3.5mm line out with surprisingly good headphone presets. On the performance side, I talk real-world gaming use and measurements: near full sRGB coverage, advertised 99.5% DCI-P3, solid uniformity, and all the motion clarity tech you’d expect (0.02ms response time, G-Sync compatible, FreeSync Premium Pro, and ClearMR 21000). But I also call out the stuff that matters: you need a strong rig (even my 5080 + i7-13700K only hit high 300s/low 400s in Fortnite on low settings), LG’s 2-year OLED warranty is shorter than the 3-year standard I usually see, and the potential deal breaker for some is the matte coating. If you’re serious about esports speed, it’s a real contender—if you prioritize resolution and max image quality over speed, it’s probably not for you.