Temperature And Noise
We don't like to compare reference coolers to aftermarket solutions. Unfortunately, with no reference GeForce GTX 660 Ti to represent Nvidia's latest, that's the situation we're faced with today. Without question, MSI's Twin Frozr-equipped solution is heavily modified, so we don't have an apples-to-apples comparison versus AMD's (infamously bad) reference coolers. Fortunately, AMD's add-in board partners swap those out just as often as Nvidia's do.
The GeForce GTX 660 Ti puts up numbers that are very similar to AMD's reference Radeon HD 7870. In this case, the more aggressively-tuned card suffers the disadvantage, as MSI’s model is rated for up to 190 W instead of the base specification's 150 W ceiling.
There aren't many other surprises to point out, except the penalty suffered by the Radeon HD 7950 with its "GHz Edition" firmware. The power-hungry GeForce GTX 580 is less than impressive, too.
This is where we see AMD's reference cooler compare poorly to the cards from MSI, Gigabyte, and Zotac. You'll simply have to remember that, should you snag an AMD board with aftermarket cooling, it'll perform differently.
Again, AMD's fans underperform. We've seen in stories like Radeon HD 7950 3 GB: Six Cards, Benchmarked And Reviewed just how much impact a more thoughtful implementation can have on acoustics and thermal output.