That’s a very big file for SU and most machines will struggle with it, if I understand correctly.
I’m working on one that is around 250MB, with about 14 million edges and tens of thousand component instances, and while I haven’t had out of memory errors (I use an i5 iMac Retina 27" with 24GB memory), if there are a lot of layers turned on, everything slows to a crawl, inferences take ages to appear, and generally, it can overwhelm the machine.
SU might just genuinely be ‘out of memory’ but that’s a guess on my part.
Maybe someone more techie than I am might be able to advise you better.
Have your regularly used Model Info/Statistics/Purge unused? If not, try that, or other techniques to reduce your model size.
If you have imported a lot of 3D warehouse models, be aware they can be colossally over detailed. See this thread for suggestions - I got the edge count down by millions, just by redrawing or simplifying models before using them in the main big model: