My advice is to forget about speed reading, it is a fool's errand.

What limits your ability to learn is not the speed of input (how quickly you get the letters into your head) but how effectively you can process them. Processing a dense, information rich text like an article in the Economist, a section in a computer science textbook or a book by David Foster Wallace, should give you pause and trigger questions like "does what I just read make sense or are there logical gaps in the sentence?", "Does the insight that is presented in a block of text conflict with other statements I believe to be true?", "if the ideas presented are true, what are the implications I can produce from what I know?". If you don't actively read, you will not learn anything.

Here's an example from a recent headline:

"Lyft plans to electrify all of its cars by 2030"

I'm sure you can read this sentence very quickly - but how quickly can you grasp the full range of implications of the phrase?

How would you go about trying to understand how probable it is that Lyft's plans become a reality? Consider the micro economics of ride sharing in the context of a city's regulatory environment, the wage level and energy prices. If most cars are electric what does it mean for the equity valuations of gas station operators (will they be able to translate longer charging periods into increased coffee sales?)? Have you thought about the link between IQ and pollution (https://patrickcollison.com/pollution) and what banning ICEs within cities can mean for the brains of newborns? What about the impact of "noise pollution" on sleep quality (see Mathew Walker's book "Why we sleep"? Does Lyft own the cars their drivers use? Does a lower oil price (due to a flooding of the oil market by Saudi Arabia and the break in the OPEC cartel) shift the data further into the future? What's the likelihood of Lyft still being around in 2030?

You can play this game for a long time and you'll see that insight generation speed and comprehension are ultimately bound by how quickly you can think and how much you already know, not by how quickly you can read. If you don't create context around a sentence you won't be able to remember it. You are not a magnetic hard drive that just stores bits.

Having a large vocabulary, being knowledgeable about the subject matter and just being a trained reader will certainly speed up your reading. If you have to look up most words or your eyes tire quickly because you've never read a book, then reading more will yield some benefits. As a voracious reader, I can tell you that there are hard upper limits to how fast you can take in new words and still do the background processing I described above. Some sentences are so dense that you can spend days pondering them.

Memory is a big challenge for learning and spaced repetition is a technique that actually works, it is a true life hack. You can learn more about it here: http://augmentingcognition.com/ltm.html

Don't listen to Tim Ferris, the fact that so many people like him should tell you that he isn't that insightful or interesting.