leoflow :
My idle CPU temp is around 40-42c, I use the cooler that my CPU came with. Is 40-42c fine on idle? If not what should I do?
What utility are you using to read CPU temp? On 'X' CPU's temp is reported 10 deg. C higher than actual temperature, for cooling policy reasons, and some utilities might factor that off-set out so it's important to know which.
If you are using HWInfo64 (highly recommended for this and other reasons) it reports TWO temperatures: Tdie and Tctl. Tdie is the actual temp while Tctl is the offset temperature as reported.
If you're using a utility that only reports motherboard temperatures then god knows what the true temperature might be since every mfr. locates and calibrates their sensor differently.