Just some advice, STAY AWAY FROM EVERYTHING RELATED TO THIS SERIES TILL YOU HAVE READ THE LAST BOOK AVAILABLE.
Some kindly advice:
Step. Away. From. The. GRRM. Author. Forum.
Biodroid, I cannot stress strongly enough that you follow the advice of these posters.
Martin really throws some curves into the story. Nothing that's not been done before, but he really pulls off the plot twists unlike most almost all current fantasy authors. I'd like to say that "even I" did not see some of these developments coming, but that'd be overstating my powers of prognostication... in fact, Martin caught me with my pants down. And I love him for that. Uh, that does not sound too good, but you get the picture.
Also I did not even think about the mathematical equation... there is a theory that is expressed as an equation most of the time... and I should have seen it coming. But ever since I read it here... it has been gnawing at the back of my brain.... for five years.
As for Tad Williams, I read
The Dragonbone Chair and got about a third of the way through
Stone of Farewell. Williams bored me with the first four-fifths of
The Dragonbone Chair, but he really brought things together at the end. Even though I was disappointed with most of
The Dragonbone Chair, I picked upon the strength of TDC's conclusion. Yet Williams again slowed the pace down to a crawl... tedium, is what I'd call it. Obviously, Williams can spin a yarn when he wants to, but his idea of character development, world building and creating tension leave much to be desired. Then again, I think I might have liked Williams thirty years ago... when I was fourteen.