If you watch back past episodes of the VFTLS (I can't tell you which one), you will find a very detailed explanation from Martin why this is not possible. In short, it is a limitation of the underlying technology (hardware etc) not vMix. Consequently it is not recommended to use multiple GPUs.

I assume it stops to 4 because it recognises only 1 gpu or it "freaks" somehow it confuses the ports between the 2 gpu from the system. Or because the outputs in vmix are 4 and most of cards dont have more than 4. The thing here is simple. Vmix is awesome software. But OBS has some functions,that users ask from vmix team for years! So your best bet i personally believe is to share your workflow between vmix and OBS or other software that can use your 2nd GPU outputs.This is what im doing some times because i cant find such "complex" solutions in vmix.
Also if you search the forum you will see many requests for making more outputs and fullscreen. Into this for the limited outputs some people say that because the trikaster that costs at least about 10x times that vmix software costs,has more outputs but it also it is a pc box,so vmix can have more also but for now it doesnt have.
But un-fortunatelly the thing is "take it as is,or leave it". Un-fortunatelly this is for any product either is software or hardware for most people that we are not programmers ourselves to do our custom solutions or dont have the budget for this. I also had a hope that vmix 28 will have more fullscreen outputs,but no. We wait now for this function vmix 29,30 or who knows when!

They absolutely do hardcode things like this.

But "arbitrarily" is a bit harsh.

They do it based off what they believe machines will support.

Historically, there's been an emphasis on saving people from themselves.

Which makes sense, because it's their reputation on the line and it's their team that has to provide customer support.

I don't necessarily agree with the choices they make sometimes on what lines they draw or where they draw them, but I can generally see where they're coming from in drawing them there.

While you may know better and I may know better, look through some of the posts these forums. Do you really think they all know better? And can you really begrudge Martin, etc. for not wanting to deal with them pushing their system beyond the boundaries that we'd know it could handle?

The simple answer is that most people who don't know what they're doing probably don't have connections for 1,000 cameras or a NIC that can support 1,000 NDI inputs.

Both are physically impossible.

When they try and fail, they aren't going to vMix and screaming about how it's their fault that they don't have enough PCIe lanes to connect to that many cameras or a network card that can't handle the bandwidth of that many NDI inputs.

But if they try to use too many Outputs and vMix crashes, a lot of people won't be that introspective.

There was a thread we were both part of, what, about a week ago? People were very upset that Apple took away the ability to use external Lightning microphones in Safari with iOS 17.

And they proceeded to demand that vMix fix that issue, because it was vMix's website where they first encountered it, so, therefore, it must be vMix's problem to fix.

At least one of them even contacted support directly to demand an explanation after both of us explained to them that they were complaining to the wrong people.

Like I said, there may be a number of us who'd know it's not anyone else's fault if we overtax our system, but other people--like the ones who think it's vMix's problem when Apple disables the ability for their browser to see certain microphones--will only see how they tried to use vMix and it crashed.

That said, I think they've gotten better with it.

v27 included the change to 4 hardware Externals with the caveat that people should be very careful using it because they didn't think most machines could handle it.

And Martin has talked a bit about a plan to remove the output limit.

You`re right but the outputs 5-7 is another GPU and not the main one that vmix use. So i believe that they hardcode it like this in order to en-sure that perfomance will not be degraded while the system need to move data between 2 GPU.Even if un-officially you order the monitors in windows in a way that allows you in the total 4 monitors to use from both GPU. Personally back at 2021 end when i started use vmix and the gpu prices were been too expensive for what they offer, i used in my i7 10th gen the intel graphics from m/b outs and a gt 1030 in order to have 4 monitors. It worked ok. I didnt have any vmix crash or a message that "dont do it". I also took the responsibillity to do what i do. So if im asked personally i dont see why not be able to use all the outputs/screens

Also something i see now is that if we go to vmix-->settings-->perfomance-->show advanced settings-->tick in order to see the hidden settings in the Graphics Adapter beyond default our GPU is appeared 1 or more times and that depends on how many connections/screens we have. For example if we have connect 2 monitors,in this setting beyond default we will see 2 times our GPU to exist.
So i dont have personally now 2 gpu to try,but one can see (and of course take the risk) if there appears also the other (2nd) gpu and proceed further by using also the option "vmix multiple instances" maybe in order to (un-official) solution

Do they monitor these forums? How would I so an official request?

Again, I am not even requesting more that two full screen options, which would increase performance. I am just requesting that they let me choose which 2 out of my seven (not four) to use. Rather than use some arbitrary left to right, top to bottom weirdness.

It is like getting to choose 2 of your dogs to go on a road trip with you. But you only get to choose 1-4, not by name. So I have 5 dogs, lets say. So, which number applies to which dog? Whatever scheme you come up with, there will always be the dog that doesn't get a number and doesn't get to go on a road trip! That's just not fair, and it makes for an unhappy dog. LOL

Submitted.

https://forums.vmix.com/...ot-limit-to-4#post116210