Question CPU proper working temperatures ??

Nov 9, 2020
Hello everyone..So excited to be part of this amazing community.Already received a lot insight and help about pc systems reading through some of the posts..Its my first post here so i would really be grateful for any insight or advice you could provide.As i was searching some info about fan controls and issues here in tom's hardware I came across a comment from an experienced ranked memeber that an idle cpu should be in about 15 C or lower. This troubled me a bit as i completed a new built with a 10th gen i7 intel processor ,a noctua cpu cooler (nh-d15 double tower) and a phanteks case with 3 140mm DC fans . Having configured the noctua in 50% speed for temperatures below 50C i see the idle cpu temperature at 27C . Is this number something normal for this series of intel cpu's or have i placed something inproperly (probably the thermal paste ) and should be indeed having temperatures below 20 at least in an idle state .??Thank you so much in advance.