Cooling a fiber optic HDMI plug header

[Jon-Slow]

I'm suspecting that my HDMI plug on my graphics card gets too hot and causes my TV in the other room to flash and flicker in rainbow colours . All my hardware temps on HWinfo are more than fine and this doesn't happen when I use my monitor that's next to the PC itself. I know that the issue goes away if I close the door and blast the AC.

 

The fiber optic HDMI plug does get very hot and So I'm looking for a way to dissipate heat without having to leave the AC on in the room. But I'm not sure how to go about it. What sort of things exist that could help me do this in a effective way? I saw on reddit that someone put a tiny heatsink on it. Any thought?

[TempestCatto]

You could try pointing a wittle desktop fan at it, one like this: https://www.amazon.com/Gaiatop-Powerful-Portable-Personal-Adjustment/dp/B09LQN6815/ref=sr_1_4?dib=eyJ2IjoiMSJ9.Bf0llrKPboYbEdhT4_P_UxZ47yGqIEUqEi2yE8aYg2MlR6sM_Qqug8nlxbILKS856KSWskeFbQpgktfxkJx-ZMSzKxXxr57s2HOw0DvvKYs5afKcifV5zrArXnSsdjjlixUqzgTZ517ZGUbpfqxQPvti1146es24sbO-eSOjcnMTMpULPM6coyBRIuRGvSthbNojc5v0aorFsDoP5cIdjce6PGo7ZImzLKVF-1iA3i_Di1ymak67qZ7AUITn6kQn5kcRqO86BqNV7E73kLOd3j5Nt2lMyPTh3kMGaKaIRAU.uj1GXPkNVAacJjOMNfpJsoyWtraJCT2Yv79V2B-grDY&dib_tag=se&keywords=desk%2Bfan&qid=1725284407&sr=8-4&th=1

 

 

(I don't know how to shorten the Amazon link, sorry)

[Jon-Slow]

@TempestCatto Thought about a fan myself too, but looking to see if there is a smaller, less noisy solution.

[TempestCatto]

4 hours ago, Jon-Slow said:

@TempestCatto Thought about a fan myself too, but looking to see if there is a smaller, less noisy solution.

Other than buying a higher quality cable, maybe just a heatsink on either side with thermal pads squished in between. Use a zip tie or two to hold tension on them.

[Bitter]

Small heat sinks meant for 3D printer parts and some thermal tape or thermal epoxy?

[Jon-Slow]

@TempestCatto @Bitter Yeah, those are the things I'm looking at right now. I tried balancing a spoon over the cable and it somehow worked to some extended so I've orderd an M.2 heatsink that comes with a pad and will try that out. Buying a new/better +10m fiber optic HDMI would be a lot more expensive

[TPCEA]

On 9/4/2024 at 2:02 AM, Jon-Slow said:

@TempestCatto @Bitter Yeah, those are the things I'm looking at right now. I tried balancing a spoon over the cable and it somehow worked to some extended so I've orderd an M.2 heatsink that comes with a pad and will try that out. Buying a new/better +10m fiber optic HDMI would be a lot more expensive

Please let us know how it goes.

[Jon-Slow]

On 9/6/2024 at 7:21 AM, RevGAM said:

Please let us know how it goes.

@RevGAMWell I did get the cheap m.2 heatsink, but I guess I should not have gotten the cheapest option becuase it still gets hot after 10-20 minutes and the issues comes back. I exchanged the spoon with a fork and weirdly enough that does better than the cheap M.2 heatsink. I tried a pair of copper door hinges ( yes, very funny, I know) and those did better than the fork to a point where the issue is almost gone. I am done putting hosehold items on it for the time being and will probably get a proper heatsink.

[Bitter]

What's the exact cable you're using?

 

If it doesn't have flat sides then getting a heat sink to make good contact is going to be very difficult. If you have 5V available (unused USB port) at both ends of the cable then you can get a 5V small Noctua fan and even a poor heatsink with a fan is orders of magnitude more effective than an excellent passive heatsink.

[Jon-Slow]

14 hours ago, Bitter said:

What's the exact cable you're using?

 

If it doesn't have flat sides then getting a heat sink to make good contact is going to be very difficult. If you have 5V available (unused USB port) at both ends of the cable then you can get a 5V small Noctua fan and even a poor heatsink with a fan is orders of magnitude more effective than an excellent passive heatsink.

TBH it's the cheapest chinese fiberoptic I could find. It works great in terms of giving me the full 4K 120hz picture with VRR full RGB. It was like 50$. But I also live in a hot and humid place and when I'm not inside the room with the PC then I wont be turning the room's AC on. It's usually not an issue for the PC itself since I have good cooling for it, even switched the GPU fans with 2 Arctic P 14cm ones.

 

I think the current M.2 I got was too cheap and worthless to work right maybe, and I should really try better ones. I also know that at some point just putting heatsinks there could be useless if they also get saturated with heat over longer sessions so a fan of some sorts might have to be a consideration at some point although I would like to avoid that. So far I'm going to test a bit more and see what happens.

 

I really wonder if anyone else with more expensive cables have similar issues because the heat is coming off of the GPU itself. I've seen here and there people complaining about the same thing.

[Bitter]

14 hours ago, Jon-Slow said:

TBH it's the cheapest chinese fiberoptic I could find. It works great in terms of giving me the full 4K 120hz picture with VRR full RGB. It was like 50$. But I also live in a hot and humid place and when I'm not inside the room with the PC then I wont be turning the room's AC on. It's usually not an issue for the PC itself since I have good cooling for it, even switched the GPU fans with 2 Arctic P 14cm ones.

 

I think the current M.2 I got was too cheap and worthless to work right maybe, and I should really try better ones. I also know that at some point just putting heatsinks there could be useless if they also get saturated with heat over longer sessions so a fan of some sorts might have to be a consideration at some point although I would like to avoid that. So far I'm going to test a bit more and see what happens.

 

I really wonder if anyone else with more expensive cables have similar issues because the heat is coming off of the GPU itself. I've seen here and there people complaining about the same thing.

So it's only the PC end giving you trouble?

 

Keep the hot air from blowing on it. Use a short HDMI extension cable to move the heat sensitive part away from the heat source. A 3 feet (1 meter) cable would be PLENTY of distance and should not affect signal quality as long as it's not the world's worst cable. That also gives you room to make a small stand to hold the hot part off the floor with a small low power silent fan to blow on it or room to attach a large passive heat sink.

 

Heat sink can't work if the hot part inside isn't touching the case! Probably need to open the cable end and either directly cool the hot part or put thermal interface between the hot part and it's case.

[Jon-Slow]

The extension cable idea is a good one, I did think about it earlier as well but was trying to wait and see before making a purchase.

 

I did more tests by moving my PC next to the TV and trying a regular high end and short  HDMI 2.1 cable. What I found wast that If I leave the fiber optic in, then when it starts to get hot and flicker, switch to the regular short HDMI 2.1, I still get the flickers for quiet some time. So from this I could guess that this isuue isn't exaclty inside the cable.

 

It seems to me that the fiber optic cable heats up ( lots more than the regular HDMI), the heat affects the GPU port and this is most likely where the flicker comes from.

 

So I had these 2 cheap M.2 heatsinks that I had bought that didn't work on the cable, I picked them up and stuck them on top of the back of the GPU's backplate closest to where the HDMI 2.1 is on the outside. Meanwhile I still had that funny copper door hinge that is the size of an m.2 heatsink on the HDMI plug so I didn't move it. I've been trying like that for almost 2 days and the issue seems to be all gone. So just decipating a little bit of heat from that area of the GPU right above the HDMI port from the inside of the chassis seems to have done the trick.

 

I will still keep monitoring it to see how it goes. @Bitter @RevGAM

[Bitter]

4 hours ago, Jon-Slow said:

The extension cable idea is a good one, I did think about it earlier as well but was trying to wait and see before making a purchase.

 

I did more tests by moving my PC next to the TV and trying a regular high end and short  HDMI 2.1 cable. What I found wast that If I leave the fiber optic in, then when it starts to get hot and flicker, switch to the regular short HDMI 2.1, I still get the flickers for quiet some time. So from this I could guess that this isuue isn't exaclty inside the cable.

 

It seems to me that the fiber optic cable heats up ( lots more than the regular HDMI), the heat affects the GPU port and this is most likely where the flicker comes from.

 

So I had these 2 cheap M.2 heatsinks that I had bought that didn't work on the cable, I picked them up and stuck them on top of the back of the GPU's backplate closest to where the HDMI 2.1 is on the outside. Meanwhile I still had that funny copper door hinge that is the size of an m.2 heatsink on the HDMI plug so I didn't move it. I've been trying like that for almost 2 days and the issue seems to be all gone. So just decipating a little bit of heat from that area of the GPU right above the HDMI port from the inside of the chassis seems to have done the trick.

 

I will still keep monitoring it to see how it goes. @Bitter @RevGAM

Nice find. Use a short cable to get the heat off the GPU and I think you'll be all good.

[Jon-Slow]

@Bitter @RevGAM The issue eventually came back then the cable died. Maybe from me fiddling with it too much and doing something bad to it during the said fiddling. Bought a new cheap Fiber Optic HDMI 15m for around 40$ and so far it's been working great.

[Bitter]

1 hour ago, Jon-Slow said:

@Bitter @RevGAM The issue eventually came back then the cable died. Maybe from me fiddling with it too much and doing something bad to it during the said fiddling. Bought a new cheap Fiber Optic HDMI 15m for around 40$ and so far it's been working great.

Mark this as the solution I guess.