D3 force layout visualization dead slow when using a large dataset?

I doubt you'll find any option that can render 50K nodes in a force-directed layout without slowing to a crawl - most implementations are O(n3), and I don't think D3's is any different.

If offline tools are acceptable, you might check out Gephi, a desktop-based tool that can deal with very large graphs.

For more than 1k elements in force layout, consider using canvas instead of svg. It can help with rendering performance. See example here:

https://vida.io/documents/Ye5eGKJrfn3xBmnS3

You might want to try GraphGL to visualize large networks on the Web: https://gephi.org/2011/gsoc-mid-term-graphgl-network-visualization-with-webgl/

For me, it's animation that is very slow when displaying a lot of data via the d3 force-directed graph.

When I need to display a lot of nodes/links, my plan is going to be to remove the animation and have a static force directed diagram. Maybe you can try that? Yes, it's less fun, but once you have a lot of nodes, I don't think the animation is that helpful.