1.36v definitely won't scratch a 45nm cpu. but there is generally no need to set vtt (actual reported value) 0.05v higher than vcc unless vcc is below 1.20v. extra vtt voltage just helps to get around certain fsb frequencies and makes gtl reference multiplier more flexible. I believe that at vcc values of more than 1.40v a vtt that is slightly higher offers voltage overshoot protection and some noise immunity but this is just based on my understanding of how its implemented from reading through lots of intel datasheets. Safely for every day on a 45nm chip as long as you stay below 1.50v vtt there won't be any kind of chip dying happening anywhere in the near future. A vcc of 1.50v and higher will wear the chip out at a higher rate if average temps are too high in general. You could probably use 1.60v vcc and 1.65v vtt all day long if you can keep the cpu temps low enough under full load ( id take a guess and say < 40c full load )