The speedup comprehension effect is old news.
With pitch control it is possible to speed up audio recordings (or TTS) by a lot without impacting comprehension. Humans can process speech much faster than anybody can speak.
From there to intelligence boosts *because* of the faster data flow is a tough point to make, though. Hard to even construct a proper test to modern standards.
The correlations that have been found in experiments going back to the 50's actually point to an opposite causality: higher intelligence leads to a higher speedup limit to comprehension.
http://books.google.com.pr/books?id=...0pitch&f=false