To anyone who's curious, in practice my impression is that it makes a HUGE difference. Processor performance on the 980 box is much MUCH better than on the power-strained TI box, which I'm sending back. When overclocked to the same speed, the TI box with identical settings hovers down below 2 Ghz most of the time while the 980 box is up above 4 most of the time w/ load. The disk performance ( same exact drive, just moved ) w/ rapid mode, which is very proc dependent is also much better on the 980 box, breaking 5 GB/s read/write. So, yeah, question answered. The 980 box is also quieter, which I adore. Good thing I don't play many games and the card difference isn't a huge deal, or at least I keep telling myself that.