I like how at least the BlazeGraph people are talking about billions of edges and not thousands, but I'm not sure that's something I could use. That seems to be a "pre-order" page, so it sounds neither open source nor existent. And I'm trying to figure out what their normal non-GPU non-distributed software is, but it seems to mostly be a pile of Javadocs.

Using distributed computing on mere gigabytes of data is silly.

I think TinkerPop was something else back in 2011, but apologies if I've used the wrong terminology.