The 65-inch M-Series Quantum X ($899.99) is significantly brighter than the 50-inch TV model ($629) in the same series, and offers strong contrast and excellent color performance. Light bloom is a small factor, however, and shadow details can appear a bit washed out, but it’s a step up from the 50-inch model in every other way. Moreover, since it shares the same panel and backlight design as the 75-inch M-Series Quantum X, you can expect the bigger screen to offer similar performance. Despite these strengths, the Hisense U8H ($1,399.99 for 65-inches, often available for much less) and TCL 6-Series Google TV ($949.99 for 65 inches) remain our top picks for overall value and their even brighter panels, while the Hisense U6H ($799.99 for 65-inches, often available for much less) is our Editors’ Choice for budget-friendly TVs.

The Same Design and SmartCast

Physically, the 65-inch MQX is simply a larger version of the 50-inch MQX we previously tested; we go into greater detail about its characteristics in that review. It looks typically understated and minimalist from the front, features four HDMI ports (one eARC, one 4K120 for gaming) on the back, and comes with a fairly simple remote with a microphone for voice search.

(Credit: Will Greenwald)

Similarly, the SmartCast TV platform is the same on both TVs. It has a strong selection of major streaming apps and supports Apple AirPlay and Google Cast for local streaming from your phone, tablet, or computer. It also has Bluetooth so you can listen privately to what you’re watching with headphones. 

A Brighter Picture With Strong Colors

The Vizio M65QXM-K03 is a 4K TV with a 120Hz refresh rate. It supports high dynamic range (HDR) content in Dolby Vision, HDR10, and HDR10+.

When testing TVs, we typically extrapolate test results across different screen sizes in the same line, with the understanding that they’re produced in the same way and have the same features. The 50-inch Vizio M-Series Quantum X we reviewed earlier this year is an exception, as Vizio claims the larger sizes in the series produce more brightness. While still an excellent TV, one of our complaints about the 50-inch Quantum X was that it didn’t get very bright.

We test TVs using a Klein K-80 colorimeter, a Murideo SIX-G signal generator, and Portrait Displays’ Calman software. The 65-inch Vizio MQX indeed gets significantly brighter than the 50-inch model due to its use of a panel and backlight from a different manufacturer.

Out of the box in Calibrated mode with an SDR signal, the TV showed a peak brightness of 437 nits with a full-screen white field and 617 nits with an 18% white field, with a black level of 0.01cd/m^2. With an HDR signal, those numbers increase to 565 nits with a full-screen white field, 803 nits with an 18% white field, and a black level of 0.002cd/m^2, for an effective contrast ratio of 401,500:1. That’s a huge jump from the smaller TV in the same line (443 nits peak brightness, 0.05cd/m^2 black level, 8,054:1 contrast ratio). It doesn’t get nearly as bright as the Hisense U8H (1,982 nits) or the TCL 6-Series Google TV (1,189 nits), but it’s still quite strong with deep blacks. There is a noticeable amount of light bloom with default local dimming settings, though, and tweaking settings to reduce light bloom can either make the picture dimmer or make blacks much brighter.

(Credit: PCMag)

The above charts show the TV’s color levels out of the box with an SDR signal compared against Rec.709 broadcast standards and with an HDR signal compared against DCI-P3 digital cinema standards. SDR colors are generally accurate, though reds are a bit undersaturated and yellows and magentas are slightly skewed. Its HDR colors are actually a bit better, with reds and blues almost ideal and yellows and magentas running more accurate, though cyans drift just slightly green. It’s almost identical to the 50-inch MQX, which we're glad to see.

BBC’s Planet Earth II looks excellent on the MQX, thanks to its wide and accurate color range. The greens of plants and blues of the sky and water all look vibrant, varied, and natural. Fine details like fur and bark come through clearly, both under bright light and in shade.

The red of Deadpool’s costume in the overcast opening scenes of Deadpool is balanced and well saturated, and not even slightly purple or gray. Later, in the burning lab fight, the yellows and oranges of the fire look bright, and details in shadows come through clearly, though occasionally they appear a little lighter than ideal. 

(Credit: Will Greenwald)

The TV’s strong contrast comes through in The Great Gatsby. In the party scenes, the whites of shirts and balloons look bright, while black suits and dark hair in the same frame show plenty of detail like cuts and contours. They aren’t the inkiest blacks, and light bloom from the backlight array certainly comes through, but the blacks don’t appear washed out. Skin tones also look balanced and varied.

Improved for Gaming

The 65-inch MQX is quite capable for gamers thanks to its variable refresh rate (VRR) with AMD FreeSync Premium and auto low-latency mode (ALLM).

Testing latency with an HDFury Diva HDMI matrix, we measured an input lag of 5.8 milliseconds in game mode, well below the 10ms threshold we use to consider a TV good for gaming, and almost a millisecond below the 50-inch MQX model we previously tested (6.7ms).