Ahhh my bad...I thought you said you were helping Mark's subjects...
Instead you were aiming it at beginners! He asked about software not camera settings and seemed perfectly aware of noise on higher iso settings but hey ho.
I felt your comment was patronising and unhelpful. If we all answered questions that werent posed or covered every angle then each thread would be massive. There is also a beginners section for this kind of info.
For info, I could shoot the Milky Way at very low iso but sadly the MW gets lost in big streaks as the damn stars move. I'm therefore forced to shoot at a lower shutter speed, meaning higher iso than I would like, thus causing unwanted noise. Hope this helps any beginners out there and helps in understanding that there are subjects that simply have to be shot with a higher iso than is ideal.
Silly ignorant old me, I do humbly apologise.
To the OP and back on topic, I also use lightroom for general noise reduction and Nik's Dfine 2 on a new layer so I can mask and blend in PS if I need to be selective on the adjustments.