Vizio’s P652ui-B2 4K UHD TVs has a feature and specification list that reads like the Holy Grail of LED LCD TVs: a 65-inch screen (3840 x 2160 resolution), local dimming (with 64 zones), “plasma-like deep blacks,” “240 Hz effective refresh rate,” H.265 (HEVC) decoding, built-in 4K Netflix 4K streaming, upconversion to Ultra HD resolution, and 5 HDMI inputs. All for an inexpensive price.
But those are just specs, so we put the P652ui-B2 through our usual tests and observations. Does the P652ui-B2 perform like a high-end 4K TV? The results are revealed after the break.
Styling and Design
The Vizio P652ui-B2 is a flat screen surrounded by a thin black bezel. Its supplied table stand is centrally located, making it compatible with most TV tables. The rear, side, and bottom split the input and audio output connections. The depth of 2.2-inches, thick compared to other 4K edge-lit models, is necessary due to the additional space required for the direct-lighting LEDs. Overall it’s not groundbreaking but attractive.
Features
Beside the aforementioned direct backlit LEDs with local dimming, the P652ui-B2 includes what Vizio calls “Pure Pixel Processing.” Their website describes it as “A collection of picture processing innovations removes unwanted artifacts and improves edge detection to deliver the ultimate clarity in every detail.” See our performance section for our test results on that.
The TV also includes major streaming services including Netflix 4K, Amazon and Hulu Plus. We checked out Netflix HD and 4K and both performed glitch free (even over WiFi).
It does not incorporate 3D playback.
The remote control is a two sided affair, with a QWERTY keyboard on the rear. While the keyboard is backlit, the front side is dark, making it impossible to read with the room lighting set low.
Connectivity
Vizio states on Amazon and elsewhere “5 HDMI ports with support for the latest HDMI standards.” However, it turns out only one of the HDMI inputs will accept 2160p/60 signals (part of the latest standard called HDMI 2.0). The 4 other HDMI inputs will only accept 2160p at 24 or 30 Hz. This means they are, at best, HDMI 1.4 (Vizio does not specify the version).
This is likely to keep costs down, but it could present a potential future problem for consumers. If they end up purchasing two 4K sources, such as a 4K media player like the Sony FMP-X10 and a 4K Blu-ray player due out in Q4 2015, only one will run at the full frame rate. Again, since most scripted TV shows and movies are 24fps, this may not be a massive deal, but it could be frustrating down the road.
The Vizio website also states the P652ui-B2 has HDCP 2.2, a decryption scheme that will be required for playback of 4K UHD Blu-ray discs (according to published reports) and possibly other future source boxes. The owner’s manual reveals HDMI inputs 1, 2 and 5 are equipped with HDCP 2.2.
There’s also a USB port and a combination composite/component video input.
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Performance
After adjusting picture settings and calibrating the TV to SMPTE standards, the white (100 IRE) level was 50 foot-lamberts, while the black (0 IRE) level was 0.011 ftL with local dimming (LD) turned off. This equates to a good contrast ratio of 4545:1. Images were sufficiently bright but black levels were definitely not exemplary. With the backlight maxed out, we measured a light output of 125 ftL, and with local dimming turned on, black levels were exceptionally and unmeasurably dark (the backlight simply turns off).
LED Local Dimming Off
LED Local Dimming On
The sample had an obvious unevenness to the image uniformity that was visible with test patterns, and it had significant light leakage on the left edge of the screen. The uniformity was only visible in dark scenes with bright objects that didn’t kick in the local dimming (more on the local dimming later), though the light leakage was visible more often. It might be particular to this sample.
Left Edge Light Leakage at top of photo (portion from photo above, turned 90 degrees right)
We performed the HQV upconversion scaler tests for 480i and 1080i. The results weren’t great.
With the 1080i HD HQV test disc the TV passed the noise reduction and jaggies test, but failed the film resolution 3:2 pulldown detection test. The P650ui-B2 is supposed to have an option for 5:5 pulldown for 24-fps-based content, but I couldn’t find any way to enable it, even after checking the owner’s manual.
Though not common anymore, we tested 480i as well, and the results were below average. On Input 1, using a 480i composite signal, the P650ui-B2 received only a 3-out-of-5 on the Jaggies 1 test, very poor compared to the dozens of TVs we’ve tested in the last 5 years. The Jaggies 2 test failed completely. The flag test failed too, it was covered with jaggies. This test has passed every other HDTV and UHDTV we’ve tested for at least 5 years. Noise reduction and 3:2 pulldown passed, but most of the film cadences failed too.
We moved back to HDMI, and switched the cable from the HDMI 1 input to the HDMI 5 input. An on-screen warning appeared stating that the HDMI 5 input should only be used with UHD 2160p signals. This warning disappeared after a few seconds, but we quickly learned why it was there: The input fails the jaggies and film resolution tests with 1080i signals. The only test the P650ui-B2 passed on HDMI 5 input was the noise reduction test (when we enabled the noise reduction circuit). We conclude there is no apparent signal processing to reduce upconversion artifacts when using HDMI Input 5, it simply doubles the content horizontally and vertically to fill the screen.
On-Screen warning HDMI 5 when fed a 1080i signal
Having only one input that is intended for 2160p sources with HDCP 2.2 (an encryption/decryption scheme) could present an issue with folks that will buy more than one HDMI source which requires HDCP 2.2. Currently only the Sony FMPX10
Late next year there will be a 4K UHD Blu-ray player, and it too will require HDCP 2.2. Also expected will be 60 frames per second content. The combo will only play on the P650ui-B2’s HDMI input 5. An owner would either have to manually swap source devices or purchase an HDMI 2.0/HDCP 2.2 external switcher. Currently there are no consumer HDMI 2.0/HDCP 2.2 HDMI switchers and early units may cost hundreds of dollars.
Clipping of signal below 16 Local Dimming Off
Looking at test patterns, we discovered this Vizio will only display signals from 16 to 235 steps with an RGB source. The Playstation 3 (PS3) and a number of Blu-ray players display details that are blacker than black (below 16) and whiter than white (235). These limits will clip these details without a setting change on the PS3.
We played with the local dimming control called “Active LED Zones”. Activating the control does two things, according to Vizio reports and press releases: it dims the LEDs within 64 zones and activates a dynamic contrast where the TV decides if it should make darker areas darker and light ones lighter. The local dimming is aggressive, to say the least. It definitely makes for a better black level than even some more expensive UHD models we’ve seen, but at the same time there are some sacrifices. This control, while activated, would make a meaningless measurement of gamma, so we tested gamma with the Active LED Zones in the off position. The gamma measurement was mostly even, with an average of 1.93 at the 2.2 gamma default setting and 2.19 at the 2.4 setting. Gamma tracking was OK , but you’re more likely to watch the TV with the local dimming feature on, which completely changes the gamma to be less linear. More on this later.
Gray Uniformity
Color measured well, overall. Pre-calibration, factory default color points were as follows (Rec. 709 coordinates noted for reference in parentheses): Red x=0.621, y=0.330 (x=0.640 y=0.330); Green x=0.295 y=0.605 (x=0.300 y=0.600); and Blue x=0.157 y=0.042 (x=0.150 y=0.060). A color management system permits adjusting the P652ui-B2 to get the TV even closer to the 709 HDTV standard. Post adjustment readings were Red x=0.6267, y=0.3298 (x=0.640 y=0.330); Green x=0.2943, y=0.6026 (x=0.300 y=0.600); Blue x= 0.1588, y = 0.0550 (x=0.64 y=0.33). The post calibration reading are good, with only red being slightly off on the x-axis, and are better than a number of TVs–even ones without a decent color management control.
Uncalibrated gray scale measured an expectedly too blue 8579K (x=0.287, y=0.306) @ 20 IRE and slightly warmer but still too blue at 80 IRE: 7595K (x-0.298 y=0.313). After calibration the Vizio read a more neutral 6552K (x=0.312 y=0.330) @ 20 IRE and 6588K (x=0.313 , y=0 .329) @ 80 IRE.
Motion resolution enhancement has two controls. Clear Action controls the backlight scanning and Smooth Motion Effect, controls the motion estimation/motion compensation (ME/MC) circuit. It creates synthesized frames between native frames. When activated (on any 120 Hz TV) motion appear smoother, however film based content takes on a look of video which is often called the “Soap Opera Effect”.
Contrary to Vizio’s claim of 240 Hz refresh rate (sometimes also written as “effective refresh rate by Vizio), the P652ui-B2, like every other 4K LCD panel on the market with ME/MC, has a refresh rate of 120 Hz.
Using our 1000 frame per second camera, we learned the backlight scanning is operational whether the control is set to “Off” or “On”. When set to off, the Vizio shuts off about one-third of the LEDs in a horizontal strip that moves from top to bottom. With Smooth Motion Effect set to “On” the black strip widens to about two-thirds of the of the screen height. We do not know why “Off” is really “Low”.
Using our FPD motion resolution disc the Vizio with both Clear Action (CA) and Smooth Motion Effect set to “Off” yielded 320 lines of motion resolution. Activating the Clear Action with the Smooth Motion set to “Off” motion resolution stayed at 320 lines. With Clear Action back in the “Off” position and Smooth Motion in the Low position the motion resolution came in around 640 lines, Mid and High read 800 lines. With CA “On” and Smooth Motion in Low also read 800 lines. Changing the setting to Mid or High motion resolution read the full 1080 lines. The FPD disc was recorded at 1080i HD.
Right top of Bond photo above local dimming off detail check
Right top of Bond photo above local dimming on-Note detail loss and darkening
Viewing Performance
We looked at a number of Blu-ray discs to assess the picture quality. As expected, the set’s color is good, and produces a reasonably vibrant yet natural looking palette for the image. With the local dimming off, this sample showed significant flash lighting (lighter areas of the picture near the edges and corners -see photo). Kicking in the local dimming got rid of the flash lighting, though it had little effect on the left edge light leak (see photo). The local dimming does create a pleasingly dark image in most scenes, creating a black level that is darker than more expensive TVs, and punchy dynamics, but one that comes with some sacrifices. The local dimming notably crushes shadow details. Increasing the Brightness control enough to compensate merely disables the local dimming advantage. The dynamic nature of the local dimming also tends to exaggerate the contrast of the picture in ways that are sometimes not realistic. Some scenes in Harry Potter and the Deathly Hollows, part 2 like when Rupert Grint’s Ron Weasely is in the forest (1:40:55) took on a solarized look, and details of the forest ground cover were obscured entirely.
We also saw a number of instances where it appeared the dimming zones were too large, interfering with lit portions of the image, as compared to a Samsung 4K TV we had on hand. This was especially true of areas adjacent to letter boxed bars, but was also visible in other scenes, like a camera pan over a dark house in the beginning of Harry Potter (01:50), where the roof of the home around a lit attic window brightens and darkens unnaturally—or at various moments in the fight scene from the beginning of The Dark Knight (07:37-10:26).
Playing movies like Mission:Impossible:3 on a BD player set to output 1080i (to simulate the output of a cable or satellite box) showed a fair amount of jaggies on titles and edges in motion, like a pan or scroll. See the scene where Tom Cruise’s Ethan Hunt and his colleague’s truck is parked outside the Vatican (0:40:30), the detailed rock wall displays tremendous jaggies and moire. Or look at office ceiling lights and tiles that flicker in The Dark Knight (0:18:45). Adding to the issue is the set’s Sharpness control, which when set to 0 doesn’t eliminate all sharpness enhancement. On the one hand, this makes the image look more detailed than competitors, but it also tends to emphasize the noise and jaggies even more, regardless of whether noise reduction circuits are on or off.
We briefly tested Netflix 4K and it played properly. We did not have specific material to look for jaggies in native 4K, so we really don’t know what happens, nor do we have any letterbox 4K content either. We checked out The Black List and the full 16 x 9 image looked sharp and clean.
The Vizio P series 4K UHD TVs are also available as the 50-inch P502ui-B1 
Conclusion
While the P652ui-B2 does produce a true 4K UHD image and has a pleasingly vibrant, dark and punchy picture that might be satisfying for the uninitiated or casual viewer, it has a number of compromises for the enthusiast. One might be able to work around the upconversion and connection issues with an upconverting BD player and a separate switcher. And the uniformity and light leak might be particular to our sample. But there’s no way around the edge enhancement that tends to make the image grainy. And the key attraction to the TV is the local dimming, which creates good blacks, but crushes too much shadow detail and overly enhances the gamma. The increase in panel resolution over 2K HD at a$2200 price does not justify the resulting picture when compared to even Vizio’s own 1080p models, let alone competitors.
Given our preference for accuracy over enhancement, HD Guru sees no choice but to award the Vizio 
P652ui-B2 1 out of 5 Hearts, our lowest rating.
Disclosure: The Vizio review sample was purchased at retail.
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