My question is, can I hook the cpu fan directly to the PSU, and let it run 100% all the time? Then, keep the rear fan on the sys_fan and use easy tunes to adjust rpms as needed? The risk here is that the MB will not detect a cpu fan, and cause a boot failure, or at least warnings.
Background - I used the following configuration to start;
CPU_FAN to intel cpu fan
SYS_FAN to rear case fan
PWR_FAN to front case fan
I didn't like this originally, because the cpu fan was just barely turning, sometimes starting and stopping immediately, due to low MB temps. I shut off smart fan control in bios, and now it runs all the time, but so to do other case fans, with which the rear seems loud.
I would like to control the rear case fan (sys_fan) separately, but do not see separate settings for it and the cpu fan in easytune5.
I think (correct me if I am wrong) that easy tune 5 adjusts all fan speeds from one setting. If you change the 20C mark from 20% to 30%, then all fans run 10% faster. So, I need to separate the rear fan from the cpu fan if I want the cpu fan always on, and the rear on only as needed.
If you wish to power up your CPU fan on something other than the motherboard, you can go into the BIOS and shutdown the alarm for CPU fan. You will have to do this in EasyTune as well (I think) or you will get warnings in Windows. Of course the danger to this is that you no longer have any indication of whether the CPU fan is spinning or not (other than looking). Another option is to buy and adapter cable that connects to your fan and has a molex connector to plug into your PSU with a fan header connector to run back to your motherboard so that the speed can still be monitored. This gives you the best of both worlds.