3-wire CPU Fan to 4-wire MOBO header?

[RRandal]

I bought a Scythe Ninja to replace the stock Intel Core2Duo E6400 HSF on an Asus P5B MOBO. The MOBO has a 4-wire header and the stock Intel HSF had a 4-wire connector, but the Scythe has a 3-wire connector. Can this be connected? It appears that the CPU fan PWM pin from the MOBO won't be used. Is this OK?

Thanks,
Rodney

[FLG]

Yes, its fine.

[RRandal]

FLG,
I spoke with one of the techs at Asus, and he said NOT to connect the 3-wire to the 4-wire header. He said to connect it to one of the Chassis fan headers.

[FLG]

You should be able to connect it to the 4-Pin header. Ive done it myself. You might just need to change the bios fan control from PWM to whatever else might be there.

Edit: The only difference is it will run at FULL speed, though connected to a chassis connector...it will do the same.

[RRandal]

FLG,
I connected it to the 3-pin PWR fan on the MOBO, and when I booted it, I got a "CPU Fan error". I think that I will try it on the 4-pin connector and see what needs to be changed...

Rodney

[FLG]

There might be nothing to change, but take a look under "Hardware Monitor".

[RRandal]

FLG,
Thanks. Will do...
Rodney

[RRandal]

FLG,
There were no BIOS changes necessary as you said, and all seems to be working just fine.

I have noticed even before switching to the Ninja that when I run Speedfan, it will not recognize the fan speeds, until I run the Asus PC Probe II utility. As soon as it starts and displays the fan speeds, Speedfan will too! Have you by chance had this happen?

Rodney

[FLG]

Glad all is well. Nope, have not seen that problem. Have you tried uninstalling Asus Probe and Speedfan, then re-installing Speedfan?

[RRandal]

Good idea... I will try uninstalling/re-installing.
Rodney

[glfredrick]

I had the same question. I was wiring up my Gigabyte MB this mornig (has sockets for CPU, Sys, NB, and Pwr) and the sys fan outlet has 4 pins, but the mounting lug is offset so that a 3 pin plug can fit it (does that make sense?).

I also have the Antec power supply, which has a fan sensor wire (goes to Pwr?) and two molex 4 pin connectors that only have the + and - power wires, and which would require an adaptor to mate to my 120 mm case fans. The PS will moniter and control my case fans if I use it that way.

Which wasy is best, and can I plug my 4 wire fan into the Sys socket?

[FLG]

fred, you really should start your own thread for questions..but there easy enough to answer right here.

4-pin Fans are backwards compatible with 3-pin plugs and vise versa. The fan sensor wire for the PSU can be plugged into the PWR connector on the motherboard. I dont think the PSU controls the fan speed, though if it does, i would plug them into a normal molex unless they make to much noise for you.

[glfredrick]

Originally Posted by FLG fred, you really should start your own thread for questions..but there easy enough to answer right here.

I was going to, but the question was exactly the same... Sorry.

Originally Posted by FLG 4-pin Fans are backwards compatible with 3-pin plugs and vise versa. The fan sensor wire for the PSU can be plugged into the PWR connector on the motherboard. I dont think the PSU controls the fan speed, though if it does, i would plug them into a normal molex unless they make to much noise for you.

Thanks.

The Antec does control the fan speed, but I'll probably let the MB do it, unless the PS also needs to know MB temps so that it can slow down its own fan. I'm thinking it will do that without the MB connection. Guess I'll find out when I light the fire the first time.

Sorry for the hijack...

[FLG]

You will be fine without it. The less fans hooked up to the MOBO the better, those fan headers can only take so much power being drawn from them, its always better to put the load directly on the PSU.