Booster 1 fan remain > @715 rpm in iStat

[GMunroe]

From what I understand the default speed of the booster 1 fan in a Mac Pro 5,1 should be 600 rpm. I am mentioning this due to the low "whirring" I am hearing with the mac on the desk 2 - 3 ft from my sitting position. I hear reports of these things being whisper silent. Wondering if I am having an issue. CPU temps remain @34 Celsius. The 5870 seems to run a little hot though.

Anyhow just wondering if this normal?

 

[pastrychef]

My Booster 1 and Booster 2 are at 1182rpm.

 

[jetjaguar]

my booster 1 fan is at 850

 

[flowrider]

I run both Booster fans @ about 2300 RPM (using smcFanControl) because I want to keep both of my W5590s cool. The slight whir is really not that noticeable.

Lou

 

[Studio K]

From what I understand the default speed of the booster 1 fan in a Mac Pro 5,1 should be 600 rpm. I am mentioning this due to the low "whirring" I am hearing with the mac on the desk 2 - 3 ft from my sitting position. I hear reports of these things being whisper silent. Wondering if I am having an issue. CPU temps remain @34 Celsius. The 5870 seems to run a little hot though.

Anyhow just wondering if this normal?

Do you have single-processor mac pro? Or Dual?

'Normal' speed for BOOST fan in single=856 rpms.
'Normal' speed for BOOST fans in dual=1113 rpms each.

 

[DanielCoffey]

Back when the 5,1 3.33 in my sig had an Apple 5870, one small SSD and one HDD I saw...

PCI 800
BoostA 856
Exhaust 600
Power 600
Intake 600

Ambient 22C

Now, having replaced the 5870 with a 7950, adding the Rocket 640L and changing to two SSDs I still see...

PCI 800
BoostA 856
Exhaust 600
Power 600
Intake 600

Ambient 24C

This is on a machine that has very recently been *thoroughly* dusted.

 

[GMunroe]

This tells me that I am actually running cooler than most. Good to hear. My main concern is that it may be the source of the steady whir I hear as all other speeds are hovering around the defaults. Tried a radio shack meter and it read 53 db at the tower, not registering ear height at my seat. +/- 60 db is as the low as meter will go..

If this is normal it's not something I am going to worry about. It gets drowned out when the forced air is on from the heat pump. Just reading posts about whisper quiet threw me off.

 

[Macsonic]

Hi GMunroe. Your Boost fans seems normal. Their fan speed also depends much on your Ambient temp.

 

[Inconsequential]

If I remember correctly the ratio for the Boost fans to the Intake/Exhaust fans are as follows:

SP: 1.425x
DP: 1.85x


So given that Intake/Exhaust min is 600, the min speeds are:

SP: 855 RPM
DP: 1110 RPM

Give or take.

 

[Studio K]

If I remember correctly the ratio for the Boost fans to the Intake/Exhaust fans are as follows:

SP: 1.425x
DP: 1.85x
So given that Intake/Exhaust min is 600, the min speeds are:
SP: 855 RPM
DP: 1110 RPM

Give or take.

I was under the impression that the minimums (according to Apple's SMC firmware) were 855 for BOOST and 600 for INTAKE/EXHAUST. 1113 (or 1110) BOOST for Dual Processor.

I've never seen iStat report any of these 3 fans on my single-processor Mac Pro spin slower than the rpm's mentioned above.

 

[Inconsequential]

Which is what i said?

The boost fans are run off the intake/exhaust fans with a multiplier.

 

[Studio K]

Which is what i said?

The boost fans are run off the intake/exhaust fans with a multiplier.

Yes, sorry for being repetitive.

I just meant to emphasize that I was under the impression that the fans should not ever spin slower than the speeds that you mentioned in your post.