New PC, and noticed Poser 11.3 (latest update), and NVidia's RTX cards (Asus 3090ti Ko), is not compatible. When I do a render in superfly, they end up black, nothing. Told not to use Branched, but end up same problem. Rendering in Superfly, and turning of features ruins the fun, purpose after paying for the software. Is their something I am doing wrong that I am getting black renders?

I think poser 11 only supported the 20 RTX Series.  12 supports the 30 series.  I'd be glad myself to hear if anyone knows a way to make 11 work with the 30 series. :)

I can't be sure as I also have a 2080 card but in Poser12, there are two ways to use the 20xx and 30xx card: the classic GeForce  and the OptiX modes, whereas Poser11 only has the classic GeForce, so that I suppose that a 30xx card should word in this mode too.

But the fact that a render remains completely black can also happen if you're rendering in Superfly/GPU mode a scene that contains an AmbienOcclusion nodes. these are so badly not supported that they are not ignored, they can have this effect.
This kind of nodes often appears in old material settings, as it was used to enhance the result of a Firefly-based render.

If your scene is huge (many items with complicated material settings) ask: we're a few to have Python scripts to remove those nodes.
And if you know and have Sasha-16 installed, you will find in its scripts collection one that removes those AO nodes.

@ Robo2010: unfortunately, you might be right:

Poser  11.3.818 Superfly empty scene render attempt with an RTX 3070 NVidia / 522.30 SD driver

I simply haven't noticed! Like many others I use Poser 11 to setup a scene and Poser 12 to render it, usually with Optix on. 

I am guessing, poser 11 will not be updated on this issue because version 12 is out. I feel like I have a vehicle with a disabled feature (turbo), I can not use. I purchased the card because of more cuda cores for 3d rendering.

The Nvidia Ampere series cards, which include the 30xx series RTX cards was released almost 2 years after Poser 11 development ended. Support for Ampere cards won't be added to Poser 11.

You can always use Superfly CPU rendering but it is slooowwwww, compared to using the GPU.  

This problem of incompatible / obsolete drivers is one reason I spent my GPU-cards' upgrade fund on a stand-alone network-render 'Box'. Its nimble Ryzen-7's 16 CPU threads are no-where near as fast as a GPU super-card, but doesn't have 'black-out' issues when scenes / scenery become too complex, common for this PC's now-ageing twin GTX 750 Ti cards...