PWM fans too loud on non-PWM board

[Likwid_Nitrogen]

I was looking to make my system a bit quieter and bought four Nexus Real Silent 80mm fans to replace my four case fans. Turns out that I bought the PWM version without knowing what I was doing.
Problem is, I've only got 1 PWM connector (for CPU fan), so a 3 pin plugin for one fan and 3 fans plugging directly into my PSU.
Plugging the fan into a 3-pin connector and psu makes it quite loud.
Is there a way I can salvage this situation short of trying to return these fans, and ordering the non-PWM versions?

Asked another way:
How can I reduce fan speed on a PWM fan aside from plugging it into a PWM fan header?

 

[Zero82z]

If the fans came with molex adapters, you can switch the pin for the fan's ground to the position for the +5v line coming from the PSU to get the fan to run at 7v instead of 12, or you can leave the ground alone and switch the positive line to the +5v position to undervolt to 5v. Aside from that, your only option would be using your board's onboard fan speed control ability if it has one, or getting a fan controller.

 

[Michael Daly]

You can connect more than one fan to the PWM connector if the output from the MB is sufficient to power more than one. I have three PWM fans on one connector (some fans have gangable connectors; others will require adapters). The only problem will be that all the fans will run at the same speed and change in the same way - if it's the CPU PWM header, the case fans will respond to CPU temps and not case temps.

 

[That Linux Guy]

If you're not ready to get funky with some fan connectors and a soldering iron, either spend more money on a PWM fan controller (Zalman has a decent one), or just return the fans. I've got non-PWM Nexus fans in my rig and it's damn quiet. I can't speak for 80mm units though.