Vizio PX75-G1 P-Series Quantum X LCD Ultra HDTV Review Test Bench

Test Bench

Full-On/Full-Off Contrast Ratio: Unmeasurable.

Measurements were made using CalMAN measurement software from Portrait Displays (, together with Photo Research PR-650 and Klein K-10A color meters and a Fresco Six-G test pattern generator from Murideo/AVPro.

Vizio claims a peak brightness capability of 2,700 nits for the 75-inch P-Series Quantum X model (and 3,000 for the 65-inch version). That might be true for small and/or brief highlights on real HDR program material, but it was difficult to confirm since the set employs an aggressive automatic brightness limiter to prevent damage when left on in a peak output situation for more than a few seconds. While we measured 2,000 peak nits, as noted, that was more than sufficient to produce the most impressive HDR I've yet seen on a consumer display with real program material.

In the Calibrated Dark picture mode, the SDR settings were configured to produce a peak white level of 144 nits (42 footlamberts). Black level with the Active Full Array local dimming on Low was unmeasurable.

In the Normal Color Temperature setting at this brightness level, the pre-calibration grayscale Delta E gradually increased from a low of 2.54 at 20% to 5.65 at 100%. Post-calibration, using both the 2-point and 11-point white balance controls, the maximum Delta E never exceeded 1.9, at 100%.

The maximum color gamut Delta E was 3.29 (cyan) before calibration and 2.7 (blue) after. The 2.4 setting of the Gamma control perfectly tracked the BT.1886 standard (2.4 and BT.1886 are close to identical), though 2.2 or even 2.1 worked better with some source material.

An SDR Saturation sweep produced an average Delta E of 1.04 and a maximum of 2.77 (the latter in blue at 100% saturation). An HDR Color Checker test, which measures dozens of widely used colors and not just the primaries and secondaries (red, green, blue, cyan, magenta, yellow) produced an average Delta E of 1.1 and a maximum of 2.7, the latter at 100% blue.

(Delta E is a figure of merit indicating how close the color comes to the D65 HD standard at each point in the brightness range. Values below 3—some experts allow for 4—are generally considered visually indistinguishable from ideal.)

Using the Leo Bodnar image lag detector, the Vizio in its Calibrated Dark Picture Mode had a lag time of 100ms with the Game Low Latency mode turned off and 25.7ms with it on. In the Game mode, the lag was 81ms with Game Low Latency off and an excellent 16.3ms with Low Latency on.

Ultra HD/HDR
Full On/Full Off Contrast Ratio: 782,642:1

In the Calibrated Dark Picture Mode, the measured peak white level with a 10% white window was 2,074 nits and the black level 0.00265 nits for the measured full on/full off contrast ratio shown above. At a gamma setting of 2.4 the Vizio's EOTF curve follows the standard as closely as any HDR set we've yet measured, though a 2.2 setting proved better at preventing black crush.

The pre-calibration white balance Delta Es of the Vizio reached a maximum of 7.9 at 100%. Post-calibration using only the 2-step controls, the maximum was 2.63 at 80%.

The pre-calibration color DeltaE for HDR measured a low of 1.7 in yellow and a maximum of 7.5 in green. While use of the color management system adjustments improved these numbers significantly, this required extreme settings of the CMS controls, so I chose to proceed without CMS corrections. A color checker analysis without the CMS showed a post calibration average DeltaE of 2.1 and a maximum of 6.3 (at 100% cyan). Non-100% Cyan was 4.7, green 4.2, and all other color DeltaE's were below 4.0. A DCI-P3 post calibration saturation sweep was fair, deviating the most in cyan as the color checker test suggested. The PX75-G1 achieved 83.9% of BT.2020 and 97.6% of P3 (1976 standard).

HDR luminance measured 1,000 nits with a 2% white window. A 10% white window measured 2,000 nits, a 25% window 1,800 nits, and a full 100% white window 600 nits.

The Vizio passed most of our standard video tests (upconversion from 1080i to 4K at 2160p) with no issues. The 3:2 HD test was borderline, failing only because it didn't match the upconversion performance of an Oppo UDP-203 Ultra HD Blu-ray player.


SuicideSquid's picture

I have a 65" vizio M series from 2018 and I love everything about the TV except the stupid menus.

It's mind-boggling that menus on my 386 computer from 1989 are snappier than menus on my 2018 smart TV.

drny's picture

Thanks Tom for review. I'm waiting on the new soon to be released Quantum X at 85" screen size. Vizio is supposed to have improved it's processing chip and interface. If the reviews bare out the improvements, and its price at $3,000 or less then it would be the deal of the year for a premium 4k.

Woofy98102's picture

I purchased and mounted this TV in December and I'm mystified by some odd discrepancies in the review. Strangely, the picture of the remote is entirely different from the remote that I have! My remote is surprisingly heavy, with it's main body made of satin-finished aluminum that matches the aluminum trim on the TV. The remote's keypad has a seamless black rubber surface with raised buttons. It's very attractive with a solid luxurious feel to it with a really clever spring loaded drawer for its batteries that pushes in and then springs out from the slender bottom of the remote.
The other thing about my set that seems at odds with the reviewer's experience is the responsiveness of the set's user interface. My set is hard-wired to the house's gigabit ethernet network and the interface responds smoothly and quickly to the remote's input, in my limited experience. I have not tried Vizio's app control, yet. Accessing Hulu, Netflix and Amazon Prime is nearly instantaneous and definitely comparable to my FireCube and Roku Ultra boxes.
And the picture? With some of the better 4K HDR content, the picture is eerily three dimensional as if the image we're seeing is really on the other side of the world's cleanest pane of glass.
But I have to admit, playing Mariokart on the Nintendo Switch console on this TV has made me nauseous from motion sickness more than a few times. Now how many TVs can do that?? Most importantly for me, rapidly panning images on this TV do not lose resolution and pixellate, which has been the primary reason preventing me from giving up my Kuro plasma panel. And surprisingly, the Vizio's black level performance is superb. Must be from all those hundreds of local dimming zones.
Thanks for the great review of a great TV! I hope lotsa people buy and enjoy this outstanding TV as much as I have.

Woofy98102's picture

I wish to make clear that the discrepancies I reported are in no way the fault of the reviewer. Ten to one, it's all attributable to the Chinese manufacturer making incremental changes within the manufacturing cycle of a product. It happens quite often, actually.

cexemef550's picture

Overall, it appears to offer a compelling value proposition in the 75-inch Ultra HDTV category.

docas71901's picture

Its ability to handle various HDR formats without the need for tone mapping is a noteworthy feature, especially considering its affordable price. - move closet

joedavidson's picture

The Vizio's optical digital output can pass lossy multichannel soundtracks in bitstream format to an external AVR or soundbar.