Well if you really have 2 fans in the front of your P180 case, when you said you used an external fan the temps decrased, this can mean 2 things; Maybe your case is located in a space where there's bad air circulation, or your front fans aren't doing their job. Because, unless you opened your case's side panel to let the external fan push the air directly in, it's quite surprising that you get that much of a difference between the 2 readings you posted on your HDs. Also you didn't note where your "TEMP1" "TEMP2" TEMP3" where taken, so it's hard to tell exactly what part of your systems is at what temp. Also all the temps you posted, apart form the HDs, aren't that high, i mean, if for example 37C is your CPU temp, well that's not half bad. So, unless you start having stabitlity problems, you should try and plug your case fans on a "normal" molex and be done with it. And BTW, i recently built a high end 2.9GHz OC'ed Opteron 165 with an Antec PSU, and with everything running @ full throttle, the PSUs fan never spins up past ~950-1050 RPMs, and the temps inside that case where much higher than yours.