Mac Pro running Hardware Test

you need the OEM DVD to run AHT

Before you give up, install SmcFanControl 2.x, it over-writes the fan plist and can be all you need. Also gives you ability to set various minimum threshold fan speeds.

Ravi,

The sound you hear is the fans INSIDE the heat sinks. These are called the BOOST fans.

So it sounds like you've narrowed it down to those 2 fans.

Now that SMC fan control is installed, you should be able to see the fan speeds for each of your fans. What is the fans speed (rpm's) of your BOOST fans?

You can see this info when you click on the icon in the top menu bar---there's a drop-down.

Go ahead and list ALL of your fan speeds. I'm just curious.

My recollection is that the minimum speed for BOOST fans on 8-core model is 1100 Rpms. That's when it is CPU is not stressed.

If your BOOST fans are running fast, then perhaps your CPU's are under load.

Have a look at Activity Monitor and see if there is some process that is working your CPU's hard.

You can see your CPU temperature with a free app called 'Temperature Monitor'. It would good to know what is the temp of your processors.

I think that it is OK to leave the side panel off while running the mac pro.

I don't think that it should matter which HD bay your OS X system drive is inserted into. I can't imagine how that would affect BOOST fan speeds. But, if removing it from Drive bay 4 solves the problem, then it's best to avoid bay 4.

I am glad that you discovered a simple solution. Do experiment with the drive placements, and report what you find regarding CPU Boost fan behavior.

Those BOOSt fan speeds are maxed out, it looks like. You can really hear those, I'm certain. VEry loud.

Something is really strange going on. The OS drive in Drive Bays 4 and 3 are making this happen? But drive Bay 1 is OK? I've never heard about that happening to someone.

Do you have Apple CAre warranty? If you do, it would be good to tell them about this behavior. It sounds easy to reproduce so they can see what is going on.

At least your temperatures are very, very cool. I've never seen CPU temps so low as those. 5000 rpm's really keeps things cold in there.

One more thing to try is this: Use the OS X installer app (if you've got one) to place a new, fresh installation of OS X onto another drive. Perhaps create a small partition on one of your other hard drives for this purpose. You re-download the app from App Store if you need to.

If you have the Snow Leopard disc, then you can just install SL for this test.

Boot into the new installation and see if the Boost fans speed up. If fans are all at normal speed, then you can likely rule out a hardware problem.

Message was edited by: Studio K

really? mid 30's is not u8nusual at all, very normal

smc reset with power disconnected and hit power on 10 seconds.

I would even do a clean minimal install

drive bay 4 only tends to be warmer is all

PCEi cards? other than gpu.

if you still cannot get aht to boot are you connected to front usb directly? can you try a different kb?

The hatter wrote:

really? mid 30's is not u8nusual at all, very normal

I over-reacted a bit on CPU temps. Mine are a bit higher at idle. But, my Ambient temp is 33C these days---it's summer here. Ambient seems to affect Diode and Core temps a little bit.

Perhaps wintertime will bring lower temperatures.

SMC Reset with power button held down is a nice suggestion. I forgot about that one.

Yes.

Ravi Rai wrote:

Could it really be ML causing all this trouble? Shall I try a fresh install on a brand new drive for ML?

Yes, re-install ML somewhere for testing.

And, just to be thorough, try that SMC reset where you hold down the power button for at least 10 seconds before plugging back in.

It's good that you have a SNow Leopard install to use.