Earlier quoted context omitted.
That's a fairly common thing to do though. "My IQ is 200, but I don't believe in IQ tests. By the way did I mention my IQ was 200?" (Joking aside, I think you conveyed it pretty well, though I have no real clue what a GRE score of nearly 20 years ago means relatively speaking, or how you can convert it into a measure of intelligence at all...)
I don't see the site I used to estimate my IQ before. But http://www.davidpbrown.co.uk/psychology/iq-conversion.html presents a calculator. And if you google around you can find other conversion charts that vary slightly from each other.
Add to that the fact that things change as you age - I scored jolly well on an IQ test when I was 14, which gives me a nice score to slap down posturing pseudo-intellectual guys who like to compare mental dicksize at parties, but I'm well aware that I'd score nowhere near that now. I don't know. As I say, I think you brought it up well, I just don't quite see the relevance.
(Weirdly, though, converting the GRE score I got when I was 21 on that calculator results in almost exactly the IQ score I got when I was 14; perhaps there is something to it..!)