Overlord Tempest X270OC, 27" 120 Hz IPS Gaming Monitor Review

After many reader requests to review Overlord’s 120 Hz 27-inch QHD monitor, we finally got a brand new X270OC in our labs. It’s the only IPS screen we know of that can exceed a 60 Hz refresh rate. We run it through our benchmark and usability test suite.

Over the past few months, we’ve covered several gaming-oriented monitors capable of refresh rates greater than 60 Hz. They all performed extremely well, and certainly lived up to their speedy specifications. But there was one thing still lacking: higher resolutions.

In the current market, a high-refresh gaming monitor is always based on a TN panel with a 6-bit/FRC color depth and FHD resolution. The speed issue is addressed decisively. Moreover, the screens that have come through our lab performed well with regards to color accuracy. However, enthusiasts plead for the greater pixel density of QHD and the superior viewing angles of IPS technology.

So far, the only company to answer that call with a quality-controlled and warrantied product is Overlord Computer, a small firm that markets gaming accessories and peripherals.

Panel Type
W-LED, edge array
Screen Size
Max Resolution
Max Refresh Rate
60 Hz, up to 120 Hz
Aspect Ratio
Native Color Depth
Native Gamut
Response Time (GTG)
6 ms
380 cd/m2
2 x 10 W
DisplayPort v1.2
HDMI 1.4
Audio  In
1 x 3.5 mm
Media Card Reader
Panel Dimensions
WxHxD w/base
25.25 x 19 x 8.5 in
636 x 479 x 214 mm
Panel Thickness
2.5 in / 63 mm
Bezel Width
.95-1.55 in / 24-39 mm
15 lbs / 6.8 kg
One year

Overlord’s best-selling line of monitors is the Tempest series. For gamers seeking the extra size and pixel density of a 27-inch QHD display, there are several different models available. You can have one with or without an anti-glare layer, for instance. Removing that layer improves clarity and detail rendering. If you can manage the light sources in your room, it’s a compelling option.

Of course, this company's main attraction is its overclockable panels. Right now, the Tempest is the only IPS screen capable of refresh rates higher than 60 Hz. And its pricing is significantly below the average for even run-of-the-mill QHD monitors. In fact, the only less-expensive ones we know of are the gray-market Auria and Catleap screens. Neither of those run above 60 Hz reliably, though.

The key to Overlord’s success with the X270OC is a custom-made control board. That single component is the reason other IPS screens are stuck at 60 Hz. You can perform the same software tweaks necessary to run at 120 Hz on other monitors, but unless the board is equipped to handle those extra frames, you'll likely see either an unusable image or nothing at all.

The Tempest monitors are essentially hand-built using an A-grade LG panel as their core part. The proprietary control boards are tested before installation to be sure they can handle higher rate signals. Heat is minimized in the chassis by utilizing external power supplies. And the end result is the only 2560x1440 monitor available able to run at 120 Hz.

Otherwise, the X270OC is a very typical 8-bit sRGB IPS QHD monitor with a W-LED edge backlight. It runs your Windows apps, games, and other software no differently than any other display. Our press sample was tested to 120 Hz prior to shipment, and we verified its operation with our test platform. But this is no one-trick pony. We discovered it performs well in other areas too. Let’s take a look.