Plugging CPU fan into PSU

[DBJr]

Hi everyone

Very nice forum site you've got here.

I just have a rather simple question. I was wondering if it would be safe for me to plug the CPU fan of my Thermaltake K450 into the PSU as I have a 3 to 4 pin adapter left over from a case fan with a wire and a mobo header for RPM sensing.

Right now, the fan is turning at around 920 RPM according to SpeedFan and according to Core Temp, the cores of my Athlon X2 3800+ are at 72 and 84 degrees Fahrenheit, respectively.

I would like to run the fan off the PSU without ill effects to the mobo, fan and/or PSU.

Since this is my first post here, I apologize if I put this in the wrong forum.:)

[jlreich]

Welcome to http://www.pcguide.com/ubb/pcgubb.gif forums.

You temps are great and noise shouldn't be a factor if the fan is running at those RPM's. Why mess with a good thing? ;)

Also if you plug it into the PSU the system will lose control of the speed of the fan. That's not good. Yes the RPM sensor will let the system know the speed, but it will not be able to bump it up when the system gets under load and needs more cooling.

[Rick]

Actually it won't allow the system to Slow the fan
With the cpu fan connected to the PSU the fan will run at top speed all the time

The 4th wire is the throttle and allows the system to adjust the fan speed up and or down as needed


This is the only draw back to connecting it in this way
Unless you count the fan getting louder all the time a draw back

[PrntRhd]

This is the only draw back to connecting it in this way
Unless you count the fan getting louder all the time a draw back
Rick,
I thought CPU fans should connect to the MB header to allow monitoring of the CPU fan rotation. No rotation detected means alarms.

[jlreich]

Actually it won't allow the system to Slow the fan
With the cpu fan connected to the PSU the fan will run at top speed all the time
Right, but his temps are very good. No reason to mess with it and have it running full throttle all the time in my opinion. :)

I thought CPU fans should connect to the MB header to allow monitoring of the CPU fan rotation. No rotation detected means alarms.
If the RPM wire is hooked up to the motherboard header it will sense the RPM's and not think it is dead. Many 4pin adapters come with an RPM wire going off to the side to plug into the header. Or you can just turn that function off in the BIOS if you want.

[DBJr]

When I run my antivirus scan, around the last 10 minutes or so, the temps maxed out at around 135 degrees Fahrenheit at nearly 100% CPU usage but only momentarily before dropping down again.

The fan did kick up to around 1,000 RPM at that point.

My antivirus program is Norton, I know, I should get rid of it and might very well when the subscription is just about to expire.