Intel SB Stock Cooler: PWM vs Voltage control

[flopticalcube]

My mobo (Gigabyte H67N-USB3-B3 ITX) allows control of the HSF to be either PWM or voltage. I started using it as PWM but the idle speed of 1300 RPM was noticeable (CPU is i5-2500K). I changed it to voltage and the idle speed dropped to 500RPM and the fan noise is buried beneath the PSU fan now. Prime95 shows only a few degrees difference at top temp even though fans are running about 20% slower (I lowered the slope a little too). I was thinking about buying a quieter cooler but not now. Just thought I'd pass on this little trick if your mobo can handle it. Apologies if this has already been posted.