beatthegmat wrote:GMATPrep is the most accurate indicator of your actual GMAT performance on the market. Unlike practice tests prepared by GMAT prep companies, GMATPrep features real but retired GMAT questions.
If you got a 780 cold, then you may be in the 0.001% of GMAT test takers who are simply naturals. I'd still spend some time prepping, perhaps minimally in your case, and take the second GMATPrep. If you get a similar score again, then take the real GMAT ASAP.
By the way, I'm super jealous.

Well, it's not purely cold. I had studied very hard (i.e. crammed) for a week before taking the practice test, during which I took a few Manhattan GMAT tests before the GMATPrep, getting a 710, 690, 700 respectively. So, getting a 780 was totally unexpected.
I guess I'm trying to figure out if I should study for the RC and CR sections. I took the free practice test from Kaplan, the one linked on this site, and I got all the RC/CR questions correct.. Although, I don't think that test is computer adaptive. On the GMATPrep test, I got all the RC/CR questions correct, except one RC that was simple. However, on the MGMAT, I was getting only around 50% of the CR, and only 80% of the RC. So, I am a little confused on which test is more reflective of the true difficulty of the actual GMAT. The worst thing that could happen is to be shellshocked during the test, and then screw up the things I do know.
I am scheduled to take the test in 2 weeks. And, yea, 3 weeks is probably not enough to prepare, but oh well.
Anyway, I apologize my atrocious grammar. I am a little tired.