Pimax 8KX: 90hz Beta is out for nvidea 30 series cards is out,share your opinions here please

I have Pimax 8KX and RTX 3090 FE, AMD 5600X with 36GB ram. I installed the beta and NVIDIA 461.09 January driver. I have original (not optical) cable.

It’s working, getting 90hz, However I’m getting intermittent screen black outs that last 5-6 seconds. The screen just goes black. The headset led turns red and then seconds later full visual. Depending on app the frequency varies, but it happens too often to be useful in 90hz mode.

At first I thought it was turning green when I moved the headset, but that was just because when the screen went black I’d take off headset. If I keep headset on it will turn back on after a few seconds. As mentioned before depending on the game the length of time between blackouts varies somewhat.

Any suggestions on what to try to get this stable?

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Sounds like a power choke issue, could be any of the following issues related to power draw or bandwidth limitation issue due to either power constraints or bandwidth constraints when it comes to the power demands and bandwidth demands of 90hz native input mode.

What kind of motherboard? You need one with a sufficient amount of lanes. If you cheaped out I’d consider buying a good one if none of the following works

Any PCI devices besides your GPU hogging lanes?

Are you using pci-e solid state drives or sata? You should try just sata so your PCI lanes aren’t hogged

Failing that

Have you tried other USB ports? Some don’t deliver an adequate supply of power for the 8KX demands.

If it happens in all USB ports, tried a PCI-E USB 3 extension card?

Last ditch effort
Try replacing PSU with one that exceeds your usecase by 100-200w, or a gold or platinum rating one, as it’s common for older PSUs when they go faulty to cause computers to shut off entirely when not delivering enough power, the same could be happening here

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Good advice, though even high end pc power supplies will turn off when UVP trips (often undervoltage occurs in tandem with overcurrent). I had a hell of a time getting a 2070 super working on 750w power supplies even though its listed as working with 650. Ended up getting a gold 850W - the extra cost is absolutely worth not troubleshooting power issues and returning components over and over.

TBH I doubt the power supply is the issue here, but the mobo/usb controllers absolutely could be the cause. The 5V rail is isolated from 12V rail, so it’s unlikely to be related to pcie usage. Almost all psus have 120w-150w allocated to the 5v rail at most, because rectifying something like 50A is crazy expensive. I’d look into usb controllers within device manager and make sure you’re plugging the usb cords into separate controllers. Since the 8kx uses usb for power, it may be worth trying a powered hub if it seems like a power issue. Blackouts were common on my 5k+, and it was a USB issue.

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Luckily I’m not the only one who has noticed. So this is a new feature. And if you leave the static HMD it returns to that mode in about 45sec. Red led and screens off.

Please explain how PCIE lane bandwidth capacity factors into a power draw issue.

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So you can see what I was commenting on: with the latest 90hz firmware the led remains red and the screens are off, although in reality everything is active, just by touching the HMD a little the led turns green and the screens turn on. If I leave it static, in about 45sec, the screens turn off again. Does your 8KX do this in 90hz mode? if I switch to 75hz with the same 298 firmware, it doesn’t happen. Not that it bothers me, rather it seems great that the screens turn off so quickly if you do not use the HMD and also the LED turns red and so you know that it is in some standby mode. But it’s weird isn’t it?

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Not a comment on the 90Hz option but with IPD adjustment. With this Beta firmware, I have zero’d out my adjustments for clarity for my IPD. Previously I was running adjustment in Right Eye Horizontal and Both eyes vertical for sweet spot.

Re-Adjusted colour balance and backlight using Pimax Experience and all sweet.

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Motherboard is GIGABYTE B550 AORUS PRO AC AM4 AMD B550 ATX, with PCI Express 4.0 x16. O/S is on an M2

I have a PCI USB 3 extension card which the Pimax USBs were plugged into. I switched them directly to the mobo’s USB 3.2s and issue still occurred.

Honestly, I’m having trouble believing it is power or lanes issue because using the same Beta firmware and the same 461.09 driver if I switch Pitool to 75hz all the same apps run fine (no switching plugs required) just press the toggle on Pitool and same app runs fine.

Confirming I’ve updated nvidia drivers to 461.33 also and it’s working for me so far. Tested Bigscreen, AC, ACC and Dirt Rally 2 all ran ok so far. Just need to spend some time now getting fps optimal on some of these games…eg I got around 70-80 fps on AC(csp+sol) doing nordschleife.

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Does 461.33 give you any benefit though?

I think it has a vr jitter fix

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Working well for me with iRacing and Dirt Rally 2. Using 461.33 and have the optical cable.

Thanks very much Pimax

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Lindy displayport 1.4 repeater works if first cable is 3M copper cable (output cable is standard 8kx cable). Not with 10m optical! Will try more options soon. For optimum comfort I need at least 5m

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in 90hz mode? post must be atleast

Yes. 90hz. With 10m optical it works sometimes and I get weird display corruption. If I reset the repeater it works sometimes for a minute or so.
5 and 7m copper coming from same brand next days (cabledeconn)

If you have ACC, have you tried 90hz mode?

That’s good cause I just bought the optic cable.

Yes have the same issue, that the 8kx seems to go into standby when left on a table quickly and then will power up within a few seconds after picking it up.

Seems like a standby. It’s actually a good thing if it’s intended to prevent screen burn in.

If it’s not an intentional feature, it’s a bug and can be a bit worrying before it comes on again.

Using an optical cable

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Thanks for that, will install 461.33 right away

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@Alex.liu
I tested my 8k-X with nvidia 2080TI with the BETA firmware and with nvidia drivers 461.40 and 461.09

Unfortunately the displays stays black on 90hz.

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