They are a pretty good guide.
However please be aware that FSX won't use more than 1 GPU properly so crossfire and SLI setups will not be beneficial over a single GPU. This also includes graphics cards like the 6990 and GTX 590 which in actuality have two GPUs on a single circuit board.
FSX doesn't use hyperthreading either.
www.techpowerup.com has the best graphics card charts in my opinion. Find their newest graphics card review, and within will be a graph comparing every single graphics card tested before the date of that review. Look at the performance summary page for the resolution you run at.
example:
http://www.techpowerup.com/reviews/Powe ... 13/27.htmlhttp://www.computerbase.de/ has the best processor charts in my opinion. It's in german but it's not difficult to translate it using an online translator. Find their newest processor review, and within will be a graph comparing every single processor tested before the date of that review. Hyperthreading is also known as SMT, in the computerbase articles look at performance with turbo (if it supports it) but without SMT.
example:
http://www.computerbase.de/artikel/proz ... itt_gesamt