Every output voltage will have some fluctuations in the actual voltage being output. If you hooked up a volt meter to that PSU at full load, you're 12v1 might read something like 12.04v. But if you use an oscilloscope, you can actually see a little bit of bounce in the voltage. Those graphs for the noise are the output from the oscilloscope. So you can see the 12.04v would actually vary between 12.037v and 12.043v. ATX standards say the variation can't be more than 120mvs, so 60 is well within specifications. 60 and 68 aren't bad numbers, but there are some better out there. Sometimes you'll hear the term clean power and the lower the noise, the cleaner the power.
The Corsair 750TX is a good choice. It will serve you well.