8kx Native 120Hz +

Hi guys, this could be a silly proposition but here goes.

If the reason why 2x 4k screens struggle to hit high Hz is because of bandwidth, then why not increase the bandwidth… lol hear me out

Currently, both cables (standard and optical fiber) come with 1 DP (1.4 I believe) connection.

Wouldn’t 2 DP connections increase bandwidth and thus make native 120Hz + easier to achieve?

Dunno if it’s logical or if someone will explain to me why it’s stupid.

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Yes it could likely solve the problem related to bandwidth. However they would need to make essentially a new 8kX that supports 2 DP cables.

So in that we would need to wait on an 8kX v2. Of which may come later on and might even be able to do so using DP 2.0 possibly.

So no not a stupid question imho.

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So just a new cable and drivers wouldn’t solve it?

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Unfortunately that is correct as I understand it. It would need additional components and a new cable connector.

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It is how the 8kx prototypes started out…with 2 cables, as did an earlier prototype of the 8k back in the ks days if I remember correctly. I think it was originally suggested it would have to be two for the 8kx but they got it down to one over time. I assume for reduced cable weight and saving a port.

Unsure if there are any other complications outputting via two connections for this or not? As helio said though it would most likely require changes to internal hardware to accommodate dual connections at the HMD end and deal with two signals.

I imagine in time they will try and squeeze some extra hz at lower fov settings, but who knows??

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Seems pretty silly if they originally had 2 i/o’s and thought cable weight is more important than fps.

I mean, there is already a problem with eye tracking and hand tracking because they decided on 1 USB c connection for the 8kx.

So they downgraded the 8kx to 1 DP connection and 1 USB c connection, maybe to save like $100 in production costs per headset…

If that was the decision making process then it really is sad.

Here they are with a product that leads the way in some key areas but shoot themselves in the foot with such inconceivable decisions for other key aspects.

For me I don’t have two spare dp ports, so the decision to make it one was a very good one. Perspectives will always differ per case.

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It comes down to a variety of things weighing pros and cons. An extra Cable might not seem like much but a dp cable will add a fair bit of weight. Pimax was also having issues getting a dual input working well at times am guessing with some titles. As this was mentioned with switching to a single cable on the 8kX; since then they have managed to get the refresh rate capable of 90hz native on a single cable. Just still working out some kinks; so far requires a 20 or 30 series Nvidia Card and users of Amd 6000 series have reported it working.

So as @spamenigma said it is possible they can squeeze more. 5k+ was originally only 90hz then they unlocked 120 and later 144. Now only 90 and 120 support Large FoV with 144 being limited to a smaller FoV.

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Well the 8kx really shouldn’t be used with anything less than a 3000 series anyway.

So to me, if they are having a high end product then why only have some aspects being high end and not all aspects.

For people who only have 1 DP then they could have bought the 8k+ or 5k series or upgraded GPU, but alas, here I am dwelling on what could have been.

So frustrating for people who have coin and want the best product.
Seems like these decisions will lead to Pimax being the ‘what if’ company.

3000 series didn’t exist when the 8kx was being developed and released, and again this is your opinion but people have different use cases and are doing ok with 1080ti, and 2k series gpus too. I’m pretty sure it has been made with the latest of available dp components available at the time, maybe even now.

I’m using a 3090 now, and as I say I’m stuck with only 1 port available so for me the decisions on the 8kx are fine.

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The 2 DP method causes all sorts of other issues, we had many prototypes that we designed that way.

The transfer rate gain is not linear and you must also composite the signals which causes many difficult to solve compatibility and performance issues. In addition to extra cables the headset becomes heavier and much hotter as well. Further it increases the chance that when you push an update you break compatibility with some software titles and you can end up in a perpetual whack a mole scenario.

It also caused extra layers on the pcb among lots of other technical consequences. So no it wasn’t as simple as we were trying to save money as it just wasn’t practical.

Ultimately we were indeed able to achieve 90Hz at 4k per eye without the troubles introduced by dual interfaces.

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You running 4 monitors?

Most high end GPU’s have had multiple DP inputs for years, 4-5, so most people could have 3 monitors and still have 2 spare DP inputs.

Just doesn’t make sense to me, they have other headsets to fill the void of people not wanting a slightly heavier cable or don’t have the cash.

I mean, a fiber optic cable with 2x USB 3 and 2x DP would still weigh less than the standard cable.

That would make coding or whatever easier, 1 USB per screen for power, 1 DP per screen for bandwidth, they could have run 2x 4k screens at 180Hz and blown the competition out of the water.

3 monitors, and yes I have 5 outputs on my gpu (strix oc) but afaik it only supports any 4 at a time, as I believe is the case with most/all 3k series, maybe there are exceptions but I’m not aware of it.

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Did anyone think of having 1 i/o per screen?

So the cable would split at the back of the headset and become 1 leading to the GPU.

Surely this wouldn’t cause issues as the only issue is syncing the screens, which isn’t even an issue.

Fiber Optic cable would solve the weight problem.

We had many prototypes and many variants. The units I saw tried about every angle possible at that.

The team felt the method was a dead end due to the massive hassle factors and trade-offs involved with the prototypes.

Varjo ended up using a 2 interface method but their method limits the customer to 1 pc monitor (4 monitors effectively in the headset) and the performance takes a hit much larger than PP. So imagine the performance hit adding compositing *and PP in the same pipeline.

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But in theory, if 1 DP can generate 90hz for 2 screens, then 1 DP can generate 180hz for 1 screen, yes?

So mirror this and problem solved?

Uh, no. It does not work that way. That is pretty much the original 8KX thinking but ended up vastly more complex than that. Also that thinking was also part of the origins of brainwarp. Reality is a lot more difficult than theory.

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But if each screen has it’s own dedicated USB power and DP connection then it is solvable.

How this isn’t easier than currently needing to split 1 DP connection for 2 screens, I don’t get it as it’s just a mirror.

Perhaps I should take up electrical engineering and solve it.

Thanks for the replies and feedback.

Why not go further and build the first popular 8 wheeled car as well. 2x the grip!
Its a no brainer!

I love how you basically ignore all the completely valid responses on why it was a dead end. Good luck with that electrical engineering degree…

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lol, pretty lame attempt at being a smart a55.

Would you rather me not have asked the questions and gotten answers?