Converting a 4K HDMI 1.4 TV to DisplayPort for overclocking

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trey31
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Converting a 4K HDMI 1.4 TV to DisplayPort for overclocking

Post by trey31 » 13 Feb 2014, 19:08

So in another thread here on BlurBusters, there was discussion of converting a Seiki 4K TV to a dual link DVI-D input could allow for 120hz refresh at 4K resolutions. I read into it on oc net and then hard forum and the idea there was using multiple DVI-D cables and combining 2 or more main boards and splitting the signal output from each board to the panel. I'm not sure how that would work, unless it would be like doing the DisplayPort multi stream side-by-side to get 60hz. I don't really know much about how that works either because I read elsewhere that the Sharp 32" 4K monitor's MST method isn't capable of being used with video games on NVIDIA cards, so I pretty much quit looking into that display.

I have thought of a few methods I could try though. I'm sure these won't be as straightforward as described, but the general ideas should be fairly sound. Or not at all, I don't know for sure. Kind of one of the fun parts about tinkering really.

Method #1: I could attempt to get the Seiki's main board working with a separate unit's DisplayPort 1.2 input board, meaning the TV would still be running off the Seiki main board with a different input board. The downsides of this could be that the TV doesn't recognize the inputs at all, displays them improperly, or that it works but still has the current "Seiki" scaling and 24p playback problems. This is not ideal for me. Scaling and 23.976 playback should be standard on even the cheapest 32" 720p TV...

#2: I'm thinking I could grab an input and main board for a Panasonic 4K HDMI 2.0/DisplayPort TV http://shop.panasonic.com/shop/model/TC-L65WT600 from Panasonic's parts service and swap those with the Seiki's. The TV would think its a Panasonic and should attempt to do everything as though it were a native DP/HDMI 2.0 panel, right? Including processing of video, etc. So, theoretically, this particular hack could improve the Seiki panel's issues with 23.976 playback and scaling, right? Unless those issues happen to be panel specific rather than board limitations.

#3: Use a Panasonic 4K main board (to fix the 24p issue) and use a separate DVI-D input of some kind. I remember hearing DVI-D is only limited by the quality of its cable as far as data rate, but what are NVIDIA Kepler cards limited to as far as DVI-D data rates? Assuming I used the greatest DVI-D cable ever made, what kind of data rate and refresh rate would this be capable of? I was under the assumption that the max data rate is still only enough for 1080p at 120hz or 2560x1440 at 60hz with a dual link DVI-D cable. Unless that has changed, using a single DVI-D dual link isn't an option. Using 2 main boards likely isn't either, at least not for me.

The Panasonic route should be the most straight-forward approach. I know swapping all the boards and leaving the oem PSU is something that TV repair shops can do with different LCD TV models. I'm just not sure what the limitations of doing so actually are. I know I had a Samsung UN55C7000 panel operating with a UN46C7000 main board and the UN55C7000 input board, and I was told it would have worked the same with a UN55C7100 or UN55C8000 board as well, despite those having different inputs and specs/features. What I don't know is how different manufacturer boards would work together. I would assume the same way if they were similar enough. Vizio uses LG panels in their passive 3D TVs. And didn't basically everyone use Panasonic panels on plasma TVs? I think they were the largest maker of the actual plasma display panels, and by a large margin if I recall correctly.

Also in doing the math on this, if HDMI 1.4 could do 38hz w/o issue (and 40hz with minor artifacts on an overclock of the Skyworth 4K 39") at a 10.2 Gbps data rate, and HDMI 2.0 is an 18 Gbps data rate it could conceivably overclock somewhere in the neighborhood of 67-70hz right? (if the GPU were HDMI 2.0, which it is not, but for comparison sake lets say it is) I think DP is 21.6 Gbps, so based on that the ballpark for overclocking DP 1.2 should be somewhere around 80-82hz right? I'm not a cable expert by any means, but does this sound reasonable with DP and 4K? Anyone know of reports of successfully overclocking the 4K Panasonic display with the DisplayPort? So far Google has not been helpful in finding anything on this.

Anyway, the more I think about this, the more I'm considering it. Even if it ended up being a 75hz refresh for 4K, it could still get faster clocks at the "in-between" resolutions like 3600x2025, 3360x1890, 3200x1800, etc. If my math is right, which it often isn't, then 3200x1800 (which looks amazing when downscaled on a large 1080p panel, by the way) could do something in the range of 108-118hz. I have a vizio m651d that overclocks to 108hz at 1080p and it is leaps and bounds better than running at 60hz. 108hz looks pretty close to being just as smooth to my eye as 1600x900 at 120hz is on the same panel. And 3200x1800 is almost 3 times the resolution of 1080p.

"Anything worth doing, is worth over-doing."

Thoughts? Advice?

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shadman
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Re: Converting a 4K HDMI 1.4 TV to DisplayPort for overclock

Post by shadman » 13 Feb 2014, 20:07

Alot of points to reply to. I'll post some, and probably go back and edit this post accordingly.
trey31 wrote:Also in doing the math on this, if HDMI 1.4 could do 38hz w/o issue (and 40hz with minor artifacts on an overclock of the Skyworth 4K 39") at a 10.2 Gbps data rate, and HDMI 2.0 is an 18 Gbps data rate it could conceivably overclock somewhere in the neighborhood of 67-70hz right? (if the GPU were HDMI 2.0, which it is not, but for comparison sake lets say it is)
Its been known now that HDMI 2.0 should have support for 60HZ 4k, that hasn't been an issue. The only issue is it being so new, and nothing to really test it with.
trey31 wrote:I think DP is 21.6 Gbps, so based on that the ballpark for overclocking DP 1.2 should be somewhere around 80-82hz right? I'm not a cable expert by any means, but does this sound reasonable with DP and 4K? Anyone know of reports of successfully overclocking the 4K Panasonic display with the DisplayPort? So far Google has not been helpful in finding anything on this.
Unfotunately, my memory is escaping me if one is even able to overclock on DisplayPort, and my ability to google this is failing me right now. Might come back to this later. Though, DP 1.2 does have the bandwidth to support 60Hz 4K.
trey31 wrote:Assuming I used the greatest DVI-D cable ever made, what kind of data rate and refresh rate would this be capable of? I was under the assumption that the max data rate is still only enough for 1080p at 120hz or 2560x1440 at 60hz with a dual link DVI-D cable. Unless that has changed, using a single DVI-D dual link isn't an option. Using 2 main boards likely isn't either, at least not for me.
With the best DVI cable I could find, out of 5 I tried, the highest I could OC my Catleap to is 132Hz, or 531.7382 MHz. Automatic timings, however, and the display blinks alot and there are red and green lines everywhere, so unusable. Even at 120Hz, or 483.3984MHz (auto timings), I still get occasional lines, and I believe this is part of the cable/connections. So there is that information.
trey31 wrote:Method #1: I could attempt to get the Seiki's main board working with a separate unit's DisplayPort 1.2 input board, meaning the TV would still be running off the Seiki main board with a different input board.
Problem with this is, what other DP board are we talking about? Not only that, but Maarten12100 and stevemadden found that the restriction for overclocking higher than 40Hz lies not only with the input board, the the TCON board after that.
trey31 wrote:#2: I'm thinking I could grab an input and main board for a Panasonic 4K HDMI 2.0/DisplayPort TV http://shop.panasonic.com/shop/model/TC-L65WT600 from Panasonic's parts service and swap those with the Seiki's. The TV would think its a Panasonic and should attempt to do everything as though it were a native DP/HDMI 2.0 panel, right?
I don't believe so, as the Seiki has has their panels at 39", 50", and 65". I believe in the [H]ardforum thread that it was shown all three models had different connections for the panels, and weren't similar enough like that. Also, the cost-effectiveness of buying that Panasonic and replacing the Seiki internals with that would likely not be worth it. Perhaps buying a TV with a broken screen would be the best bet? :P Either way, I'm not sure the panels are the same in both the Seiki and Panasonic. We would need the Panasonic model number first.



From what I've read, and I'll source it if I need to[EDIT: This is the post I was refrencing the most: http://hardforum.com/showpost.php?p=104 ... tcount=780], is that we would need to construct new boards and materials to get 60Hz 4K working correctly, and there isn't a known way to Frankenstein this project. Maybe, by using a 4K 60Hz rated board in another TV, but it would need to connect the same way to the panel in the Seiki, and would likely need to have the same panel.

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trey31
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Re: Converting a 4K HDMI 1.4 TV to DisplayPort for overclock

Post by trey31 » 21 Feb 2014, 14:39

shadman wrote: Problem with this is, what other DP board are we talking about? Not only that, but Maarten12100 and stevemadden found that the restriction for overclocking higher than 40Hz lies not only with the input board, the the TCON board after that.
I used panasonic's parts listing to look, but I am not sure if the timing control board or input board are listed, descriptions on their site are vague. Didn't see the panel itself listed either. http://www.pstc.panasonic.com/EpartR/Pa ... Choice.asp is their parts search page, and the 4K tv's model number is TC-L65WT600.

At this point, I'll probably have to wait for an HDMI 2.0 panel from seiki, but not if it has the same refresh and scaling issues of their first models. Plus, I'd still prefer the OC potential of a DisplayPort connection (75-80hz maybe) versus the HDMI 2.0 connection (65-70hz at best), considering no current video cards are HDMI 2.0 compliant.

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