I've got an old scene I worked on in KS2 and was able to render it out with 5K square resolution as an EXR file.
I can still do that today.
After importing the bip to KS3 and/or KS4, and with no changes whatsoever, I can no longer render it due to "out of memory".
Is that expected behaviour ?
The exact same file in KS2 takes up 440.000kB .. in KS4 i got 942.588kB ? (Just opening the BIP file, nothing more).
KS4 will use a bit more memory for certain models, but this does seem like a lot. Any chance you can share it with us at info@luxion.com ?