yes it is, BUT the bottleneck will be the -- as often -- the readback.
Once you create a 7680x3240px texture you need to read it back from the GPU to the host memory to send it to other.
There are several ways to do that and without GPU texture compression I'm pretty sure you can't achieve more than 1 fps at this resolution even with the more expensive graphic card you can use gem with.
Concerning hardware texture compression, you may be interested in HAP codec (though I don't know if live encoding is available) and nvenc technology.
I think there is an embryonal external for the former but don't know any work in Pd with the latter.
so yes it is possible (like everything) but it's a huge challenge and I'll be happy to read how you achieve it :-)
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a