i used ntune yesterday for the first time. you need to understand what it does.
1) do a coarse tune or the other one, depending how long you wanna wait
2) save the profile thingamajig that it makes
3) still in ntune, create a rule (you'll figure it out
) that loads that profile thingamajig every time windows starts
it does more than riva tuner, as it does a 20 min or 3 hour stress test = more stable. it also has the ability to change not just core and ram speed (as riva tuner) but bus speed and a couple of other things.
piece of ****. (easy!)
last thing, riva tuner is good for getting and saving a graph of your temp, core, ram speeds.