Vizio p552ui-b2 1080p 120hz works!... but not quite

[KickingBear]

My p552ui-b2 was able to accept a 120hz overclock using ToastyX's Custom Resolution Utility. Out of box it could only go 1080p @60hz. and 4k @ 30hz. However, when running at a high refresh rate the screen will go black for about 3 to 5 seconds in about 10 minute intervals as if it lost signal for a second. i have tried running at 110hz, 100hz, used "lcd reduced" preset, even 720p at 120hz and it seems to do the same thing. Sometimes when trying an odd overclock like 115hz and restarting causes it to go black entirely after booting the OS until I have to go into safe mode and launch reset-all.exe. Im currently using hdmi, but i have also tried coming out DVI from my GTX 670 into the hdmi 2.0 port with an adapter and an active displayport to hdmi adapter i picked up from best buy. Behavior is the same from everything I have tried.

Right now im waiting on this Accell active displayport to hdmi adapter bc it specifically supports 1080p 120hz according to a rep I emailed. http://www.amazon.com/Accell-B086B-006B ... B00F90H9BY
Im hoping this will solve everything but I really skeptical now. Quite disappointed im having this much trouble with 120hz. I care more about that than the 4k.

I have spoken with Vizio Tech support and they confirmed it should support 120hz input and recommended trying to lower the chroma level, however the only available chroma levels to select from nvidia control panel is RGB and
YCbCr444. Both produced the same result.

What might be the problem?

[Chief Blur Buster]

When I was doing some tests on a different monitor... I found that sometimes when using a long cable, it blacked out at 120Hz more often at unexpectedly random moments.

Are you sure your problems is not being caused by the cable and/or the adaptor? Maybe try a thicker Monoprice.com cable, and a different adaptor?

Technically, 1080p@120Hz is the same bandwidth as 4K@30Hz, but some attributes may end up pushing it over the edge. When creating a monitor mode via a custom resolution utility (e.g. NVIDIA or ToastyX), try using standard porches of Vertical Total 1125 (HDTV standard), and making sure Horizontal Scan Rate is 135HKhz (1080i/60 is 33.75KHz, and 1080p/60 is 67.5Khz, and 1080p 3D at 60/60 is 135KHz) -- that represents number of scanlines output per second.

[KickingBear]

When I was doing some tests on a different monitor... I found that sometimes when using a long cable, it blacked out at 120Hz more often at unexpectedly random moments.

Are you sure your problems is not being caused by the cable and/or the adaptor? Maybe try a thicker Monoprice.com cable, and a different adaptor?

Technically, 1080p@120Hz is the same bandwidth as 4K@30Hz, but some attributes may end up pushing it over the edge. When creating a monitor mode via a custom resolution utility (e.g. NVIDIA or ToastyX), try using standard porches of Vertical Total 1125 (HDTV standard), and making sure Horizontal Scan Rate is 135HKhz (1080i/60 is 33.75KHz, and 1080p/60 is 67.5Khz, and 1080p 3D at 60/60 is 135KHz) -- that represents number of scanlines output per second.

That's very helpful thank you. I am using a six foot HDMI highspeed with ethernet cable but maybe i should try a 3 footer from monoprice just to cover all possible ground. I will play with the settings you have mentioned and update my results. Thanks again

[KickingBear]

try using standard porches of Vertical Total 1125 (HDTV standard), and making sure Horizontal Scan Rate is 135HKhz (1080i/60 is 33.75KHz, and 1080p/60 is 67.5Khz, and 1080p 3D at 60/60 is 135KHz) -- that represents number of scanlines output per second.

Ok so I made sure vertical total was 1125, i just used the lcd standard preset which did the same thing. and horizontal scan was 135kHz. Same exact issue. fine for 10 or so minutes then blank screen for 3 seconds then comes back. I went ahead and ordered a monoprice 3 footer, ill wait for that and my new adapter to come in and see if there's any difference. Im starting to think the TV just doesn't like anything over 60hz. The only other possibility i think of is that my GTX 670 doesn't like outputting 120hz into any kind of HDMI whether or not im using the hdmi output on the video card. It works fine on my 144hz monitor over dual link DVI.

[trey31]

try using standard porches of Vertical Total 1125 (HDTV standard), and making sure Horizontal Scan Rate is 135HKhz (1080i/60 is 33.75KHz, and 1080p/60 is 67.5Khz, and 1080p 3D at 60/60 is 135KHz) -- that represents number of scanlines output per second.

Ok so I made sure vertical total was 1125, i just used the lcd standard preset which did the same thing. and horizontal scan was 135kHz. Same exact issue. fine for 10 or so minutes then blank screen for 3 seconds then comes back. I went ahead and ordered a monoprice 3 footer, ill wait for that and my new adapter to come in and see if there's any difference. Im starting to think the TV just doesn't like anything over 60hz. The only other possibility i think of is that my GTX 670 doesn't like outputting 120hz into any kind of HDMI whether or not im using the hdmi output on the video card. It works fine on my 144hz monitor over dual link DVI.

I've used SLI 660Ti 3GB (and others) on a Vizio M651d extensively. The firmware of both are similar. The only way your kepler card would be the culprit is if it were faulty.

Here are my suggestions to hopefully help.

Turn off any and all video processing.

Try an nvidia driver update. If current, try to rollback. Nvidia drivers used to be why I bought Nvidia. Now... not so much.

Try monoprice's 22 or 24 gauge hdmi cables in the shortest length you can get away with. Bluerigger cables that state 340MHz spec and any 1.4 Monster cables work for me too. Amazon basic 1.4 high speed are hit or miss. I have several and 1 out of 3 or 4 had sparkly-glowy sprites over 300MHz or 310MHz.

try a custom CRU or Nvidia Control panel resolution with exactly 119.88hz refresh rate. Adjust if needed between 119.88 and 119.876, everything in that range works on the M-series, nothing above it or below it for standard 1080 resolutions or higher. Strangely everything 1600x900 or lower is fine to and beyond (albeit with frame skipping) 120.00hz refresh rates.

Also, let me know if you can get a custom resolution over 315MHz to display correctly. That's roughly the limit on the M's.

Good luck.