But...if you just want to run your own personal search engine say...
Then for Wikipedia/Stackoverflow/Quora size datasets (50GB with with 10GB worth of every kind of index(regex/geo/full text etc) ) you can run real time indexing on live updates with all the advanced search options you see under their "advanced search" page one any random Dell or HP Desktop with about 6-8GB of RAM.
Lots of people do this on Wall Street. People don't get what is possible on desktop cause so much of it has moved to the cloud. It will come back to desktop imho.