Pimax, Sparkles, and Displayport Training Mode?

I recently started getting a lot of sparkles in my headset. I figured it was static, although it’s much worse static than usual. Usually it’s a spot here or there, but now its bunches of them.

Because I had more than usual, I googled the topic and found people talking about a feature in Steam VR called “Displayport Training Mode”, which for many people solved their excessive sparkles. For example, they’re talking about it here: https://www.reddit.com/r/ValveIndex/comments/oxd6xa/psa_if_you_have_sparkling_pixels_recently_there/

So I changed to Steam VR Beta, and the option is NOT there in Settings/Video (with Advanced Settings) on.

Is it not showing because I’m using a Pimax headset? Does Pimax have their own proprietary solution? Please either help me turn on Displayport Training Mode, find the Pimax-specific solution, or maybe advise me in some way I’m not considering. Thanks. =)

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Your headset is not a valve index. Ergo no display port training mode. It is index specific.

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Ok, TY. That gets me part of the way there.

Is there no Pimax equivalent? Whatever makes the sparkles go away is my goal. Why would they suddenly increase?

The Pimax equivalent is unfortunately purchasing a new cable. They are quite fragile so stepping on them, kinking them, twisting them etc will result in choppy audio or sparkles depending on what is fatigued inside.

I am on my 4th cable for the 5K+ but still on my first cable for the 8KX. Something to do first is to try reseating the cable on the headset side, (make sure its not partially pulled out), and try other DP ports on the gcard .

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I’ll give you a little background on this. The transmit power from the GPU to the display varies. At startup (or when you connect the cable), there’s a training sequence where displayport determines what minimum voltage is required for its digital signals to reach the display reliably.

The tether cable contains many smaller wires inside, and each of those individual wires consists of individual wound strands. What generally happens is some particular spot on the cable keeps getting kinked and flexed over and over again until those strands start breaking from fatigue. Or the cable just plain suffers trauma that damages those strands outright. The cable continues to function as these strands get broken… the remaining strands are able to carry the signal. But each broken strand increases the resistance of the cable by some amount until eventually all strands for one of the wires are broken and the cable doesn’t work at all.

As the resistance of the cable increases from this damage, the GPU needs to raise the voltage in order to avoid getting bit errors… which is what appears as sparkles in the image. The training algorithm is supposed to detect this and raise the voltage automatically, but it only works up to a point.

What Valve appears to have done for the Index is provide alternative training methods that more aggressively ramp up the voltage. Which can get it to work over a damaged cable without sparkles.

Here’s the thing though. If the cable is failing from fatigue, once sparkles start, the cable is not long for this world anyway. More strands will break in whatever spot is getting kinked as you continue to use the headset, and the cable will degrade until it won’t work at all anymore regardless of cranking up the voltage at the GPU. Generally once sparkles start, the cable will reach total failure within days or weeks.

In rare cases, the cable has problems to begin with when it’s new, and the alternate training makes it happy, and so it stays happy indefinitely. But if your cable was previously fine, and it started getting sparkles because it’s failing from fatigue, Valve’s alternate training will at best only delay the inevitable by a little longer.

That said, your cable might just need reseating and cleaning. If you haven’t tried that yet (at both ends), try that first and see if the sparkles go away. Otherwise, you’ll need to buy a replacement cable. And hope it arrives before your current cable fails the rest of the way.

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Thank you, Sargon (and Honeybadger). I appreciate the in-depth explanation.

I’ll try reseating everything, as you’ve suggested.

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You should not get this “static” at all, unless it is a part of the game. The cable is faulty (or a port or connection is bad), as other said.

It looks like you are a backer so you have had this lead for some time? I typed this out before I realised but just in case …:

If it was received recently, open a support ticket before / as well as purchasing. You may get a replacement sent. Take a video, preferably showing the undamaged entire lead in use, with a view also through the lens showing sparkles, and link it in your opening message and also list everything you have already tried, and anything you cannot try e.g. perhaps :

I have tried

  • reseat cable
  • contact cleaner
  • different displayport
  • update drivers
  • differeent USB port

I can’t try a different PC or graphics card as I only have access to mine.

Also put where and when you bought it, and the order number. Give your address too.

Try and make one clear statement per sentence as they will be translating.

They will try to help if they can.

Yeah, as the others stated, once you get the sparkles it’s only gonna get worse.
I bought my 5k+ from Ebay, so who knows how long the cable had been used before me.
It did last almost 2 years though, so I’m not complaining. The fact that I use an overhead cable system and always unwind after each use probably helped prolong the lifespan.
I just replaced the old cable and while the $100 bites, it fixed the problem.
Shipping was pretty fast too. Under 2 weeks.
Good luck.

Thanks for the in depth explanation. Knew what was happening to the strands, but did not know about the training sequence on booting the HMD. That makes a great deal of sense and solves the mystery of why my failing cable would work fine for a short time before getting increasingly worse.

my 8kx had sparkles straight out of the box, a new cable solved it, but then that failed a few months later, sparkles again. i never twisted or stepped on the cable etc. i think they’re just sh1t quality cables. hope the crystal and 12k cables are better.

Yes, I was an original backer.

Might they really replace the cable this long after the fact?

No, I doubt it very much, unfortunately. But you can bear it in mind for when you get your replacement.

This happens with VR tether cables in general. It’s not because they’re badly made. It’s just a very difficult use case for durability. It’s not fair to compare them to the other cables on your PC because those cables are both simpler and rarely move. Whereas VR tether cables have a lot of wires in them and need to be as light and thin as possible. And they’re connected to a human that keeps moving and flexing the cable constantly.

My cables for my Valve Index were lasting about 6 months like clockwork. And it’s similar for my friends that use VR heavily. And it’s the same the friends that have other headsets, too.

The only headset I’m aware of that doesn’t seem to suffer from these kinds of cable failures is the OG Vive. In that case, it has multiple thick cables to the headset, and that’s apparently what it takes to be durable under use. But it sucks.

They’re using the fiberoptic cable. And as far as I can tell, Pimax’s fiberoptic cable does seem to provide greater durability. I think what’s happening is its replacing most of the tiny wires with a single relatively thick and therefore durable fiberoptic. So even though the cable is thinner and lighter than a conventional cable, it should have considerably longer life under use.

None of my previous hmd’s (dk2, rift cv1, htc vive, rift s, quest 2, reverb g2) had failing cables, and neither has my current hmd (aero) after 4 months of ownership, by now my 8kx had 2 failed cables. Sorry but i believe the 8kx stock cable is known to be weak, that’s why pimax sells a more durable fibre optic cable which should come with 8kx’s from day 1 anyway.