Strange Sound EVGA GTX 280

Basicly the title says it all, my 280 is making random high pitch hissing sounds when i run certain "heavy applications", like ati tools artifact scan, even crysis at parts and its never done that before. Recently though i've changed the TIM on the card and wondered if it was because of that, so I went ahead and reapplied it, spreading it out across the whole core with only a very thin layer, by thin I mean it, like I've read online, but perhaps its too thin, what makes me think it's good though is I get really good temps, I never pass 70C under load from GRID and such games, and the VDDC never passes mid 75C which too me seems all good. Do you guys think that's the problem and I should yet again reapply the TIM and see ? or might my card just be defective, I've had it since august, but I dunno if EVGA would take it back since when changing the TIM when I took off the casing one of the two little pins thing cracked a little, I guess its fixable though. Anywho any help is welcome

Btw, no my card is not overclocked, and I've reinstalled the applications etc. Never touched the drivers though could that be it ?