What options/settings in PrecisionX and the nvidia control panel should I be using to get the most out of my 980ti classified without overclocking it?
 
i7-4770K
Hyper 212 Evo
Maximus Hero VI
16gb GSkill Trident X 2400mhz
980ti Classified 
Corsair AX860
Samsung 840 Evo 1TB SSD
Corsair Obsidian 450D
2X Dell U2312HM 23" Ultrasharps via Display port
Windows 10 Pro 64 bit

bdary
In PX you could safely increase your power target to the max.  That will allow your card to use a bit more power without manually OC'ing it and forcing a higher core clock.  Also setup a custom fan curve to keep temps lower so the card runs at it's highest clock speed with less chance of dynamic adjustment.
 
As far as the NVCPL, you don't necessarily have to do anything, but you could go to NVCPL > Manage 3D Settings > Program settings tab > search for any of your game launchers (.exe's) and change the Power management mode to "Prefer Max Performance".

+1

I use them , but never full time . just if I want to look at something from there monitoring / setting  program  like for one game I had to use the frame limiter  feature   [mafia 1  car bomb mission is a example ] 
 
or to get a brag score in something  one time usage thing . out side of that I run my cards stock for everyday  all a round  .  for me my 980ti handles all pretty well at stock and my out of the box boost was nice over factory  speced boost clocking  anyway  .   I mean if you get a card like say that classy and the evga speced boost was 1250mhz    and out of the box your card hits 1375 boost  ???
 
like said above 
''I used them on 2 cards, and those 2 cards slowly (1) and abruptly (1) started dying on me. ''
 
I guess it can / may  cause degradation ?    in the end if I get a good solid gpu  that's better then rated factory speces   I tend not to look that gift horse in the mouth  , but to each his own  and all personal opinion on any of that