Did I screw up?

[aspire]

That was about to be my exact post. Its pretty much the same.
But yeah i think it was indeed a downgrade video card wise:

And thats the GT dont forget, not the GS. In other reviews they were close as well with the 7800GT loosing on some occasions but not by much.

And considering that its a mobile 8600GS, i think it was a downgrade.

Well considering how much faster his cpu is, a slightly slower video card shouldn't be an issue.

Consider that the review you quoted used the same cpu for each card.