hi guys, apologies if I have submitted this question in the wrong thread, I'm just after some advice please

I have a i5 4690k overclocked to 4.5 ghz with 1.2v core. I was using 1.25v and I just thought I'd lower the voltage I first tried 1.2v with prime95 the PC restarted with no errors so I upped the voltage to 1.22 and there hasn't been any issues.

I used this guide below to overclock my PC and used the exact same settings

https://m.youtube.com/watch?v=up0sZl26ei4

My PC has been running fine with no issues temps at load are around 55-60c
Idle temps are at 34-40 degrees (use to be 24-28c before overclocking). I know my idle temps are ok but as a result of the extra overclock my h100 fans kick in as soon as I turn PC on I can change them to quiet mode but I was wondering if it was possible to bring the idle temps down a bit lower.

I have read people are enabling c states and eist is this something I could look at changing because at the moment the above guide has it all disabled.

Can I, should I tweak some settings to make my PC more efficient?

I have a nzxt h440 case with stock fans
H100i GT liquid Cooler
Palit GTX 1060 Super Jetstream
8gb ram 1600

Thanks in advance for your help and advice