Neither the 7800GTX or x1900xtx are DX10-compliant. I'm pretty sure that both consoles are actually not DX10-compliant, either. I'd provide links to back that up, but I'm lazy, and if you doubt it, go check the net. You'll find plenty of articles covering the lack of DX10 for both systems.
And what makes you think that consoles are rushed out? If a game lags, it's not necessarily due to the hardware in a console, it's due to the actual coding of the game itself. It's not like MS and Sony develop every single game that comes out for their systems...If you want something rendered to look rediculously good (a la Gears of War), you'll eventually hit a point where framerates suffer. Usually, it's not something that's a big deal. Most games don't lag...but a few do for a few seconds. And if a game looks like something I'd see walking down the streets, I'm not going to care if I see occasional lag. I mean, as long as it's completely playable, who really cares?