JustG

Some of the best seafood ever is in Lisbon, Portugal, not to mention the Algrave..

Disk and Memory can both be bottle necks, however with compression on Roaring bitmaps you typically keep your entire index in memory and compute in a compressed state, avoiding slow disk. You do in fact become CPU bound on queries, even intelligent multi-threading, and CPU efficiency comes into play (especially so as a bitmap begins expanding across several shards).