[Windows Mixed Reality] Glitching Graphics And USB 3

[Avago Earo]

For quite some time, I had been experiencing a glitch in ED. Anywhere in the game, including the opening menu screen. I'll describe it as best I can, below.

In the opening menu, the scene in the hangar with the SRV and Eagle, I'd get a frame flash up momentarily (about as fast as a blink) from somewhere else in the scene. In this scenario, it would be the same orange as the hydraulic struts, so I could only guess that that was where the extra frame was coming from.

In the Docking Training Challenge Scenario, when approaching the station, I'd get a flash of the planet in one eye every two seconds or so.

In the Combat Training, the three triangle reticle that surrounds the targeted ship, would flash larger as if it was in the ship.

I had read quite a few replies to similar reports on various forums, where the majority pointed at insufficient USB bandwidth/power being the culprit as that affects tracking. Since I had already installed a Super Speed USB Hub on my Mobo, I didn't think that could be the solution in my case. However, after checking that my GPU and RAM hadn't come loose, I remembered that I had done some cable management a few months before prior to this problem arising, so I decided to use the power cable (for the USB Hub) that I used before. I didn't hold much hope, but it did the trick and now I can play ED in VR again.

I'm no PC expert (my first ever PC build from 2014), so I don't know if this helps anyone. The USB Hub is a PCIE one by Inateck, and there are two optional power cables: SATA and Molex. I have a Semi Modular PSU. When I swapped from the Molex to the SATA (just to look tidier in a windowed case), is when (I now realise) the issue began. Swapping back to Molex resolved it.

I really can't think why this would happen. The SATA cable was shared with one SSD, and an Optical Drive. I assumed that all the relevant voltage supplies were in parallel, and that one device taking a draw at the same time as another one wouldn't make any difference. Electronics is not my forte, though.

TLDR If you have odd frames from elsewhere in the scene flashing in VR, check the power supplied to your USB Hub. Just because you don't experience it in other games, doesn't necessarily mean it's an issue specific to ED, it could be that the extra demand that ED makes, reveals a USB problem in your PC set up.

I hope this is of help to anyone that is experiencing this problem. Cheers.

 

[Milner]

I've read these kind of things a fair few times in relation to VR, so not surprising but glad you found the issue.

VR gaming is a very different hardware/software experience to traditional 2d gaming, hopefully this matures quickly!

 

[Morbad]

You can get a cheap USB power tester for 10-15 bucks that will let you know the voltage of the output of a USB 3.0 port with or without a load from a component. A very handy diagnostic tool, and more convenient to use on a USB port than multimeter probes.

I assumed that all the relevant voltage supplies were in parallel, and that one device taking a draw at the same time as another one wouldn't make any difference.

They aren't. More current through the same set of conductors (wires) will lower voltage. Other components can also introduce jitter/ripple.

VR gaming is a very different hardware/software experience to traditional 2d gaming, hopefully this matures quickly!

Expecting these HMDs to be powered by a USB 3.0 port was a pretty iffy design decision, IMO.

I don't even think I can use my Acer HMD on my main system because I'm so borderline on +5v voltage with all the junk I have on that rail (nine internal and five external 2.5" SSDs/HDDs). Fortunately my HTPC is much less cluttered in this regard and my HMD works fine.

 

[Avago Earo]

I've read these kind of things a fair few times in relation to VR, so not surprising but glad you found the issue.

I got one flash frame earlier this evening when I first logged in, and considering that there is an opinion that high network stress can also cause problems; I'm happy with that. Cheers.

 

[Avago Earo]

You can get a cheap USB power tester for 10-15 bucks that will let you know the voltage of the output of a USB 3.0 port with or without a load from a component. A very handy diagnostic tool, and more convenient to use on a USB port than multimeter probes.



They aren't. More current through the same set of conductors (wires) will lower voltage. Other components can also introduce jitter/ripple.

A USB power tester may indeed be a good investment for future troubleshooting.

Thanks for confirming my suspicion that having other components daisy chained may have contributed to the problem. The reason I wasn't sure about this, is from basic electronics stuff at school; (DC) components in series have a cumulative voltage draw on the supply (as I recall), whereas in a parallel circuit, the components are straddled across + and - so the potential difference remains the same. Now I think of it though, the potential is only decided by the supply and it's destination (ground/neutral), and the draw is dictated by the components. I think I made this mistake from seeing light bulbs dim, the further along the series they went, yet all retain the same illumination when in parallel. I think I was too busy listening to The Jam, than reading my text books...

'Jitter/ripple'; I guess from frequencies from different components causing fluctuating magnetic fields getting passed along, like with 'Cross Talk' and creating interference?

[Edit] I just realised that you said 'They aren't'. So each conductor (along the SATA power cable chain) is in series? Thinking about it, without getting a haemorrhage, I guess it would have to be; seeing as it's just an extension of whatever voltage line is chosen. Well an SSD working away on the same supply as the USB to the Lenovo must certainly affect it's performance. Glad I got a modular PSU. Now all I've got to do is read some school electronic's books.