2015 13 rMBP fan activation

seadragon said:

Well, I just picked up the new 13 inch rMBP (i7/16/512)

The machine is really nice! Noticeably faster at everything compared to my mid-2010 MBP that it's replacing. And the screen looks perfect to me also. No uneven backlighting or strange tinting etc.

However, I've already noticed the fan come on a few times. It came on as I was downloading and installing FCP from the App store. And when I run Geekbench 3, it usually comes on about half way through the test. And it ramps up to what sounds like full speed. After the test, it slowly ramps back down until you can't hear it anymore.

Just wondering if this normal? I just got the thing today so I don't have much runtime on it yet.

Macbook is sitting on a table with ambient room temp around 71F.

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Fans ramping up during Geekbench 3 and large app installations are normal, because these processes take up a lot of CPU power. In fact, I'd be concerned if the fans didn't ramp up at all.

seadragon said:

Well, I just picked up the new 13 inch rMBP (i7/16/512)

The machine is really nice! Noticeably faster at everything compared to my mid-2010 MBP that it's replacing. And the screen looks perfect to me also. No uneven backlighting or strange tinting etc.

However, I've already noticed the fan come on a few times. It came on as I was downloading and installing FCP from the App store. And when I run Geekbench 3, it usually comes on about half way through the test. And it ramps up to what sounds like full speed. After the test, it slowly ramps back down until you can't hear it anymore.

Just wondering if this normal? I just got the thing today so I don't have much runtime on it yet.

Macbook is sitting on a table with ambient room temp around 71F.

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The fan is there to extract heat. It ramps up, when needed, to do so.

I'm not sure why this would be a problem?

You run task that require power. Power generates heat. Said heat needs out of the computer or it'll fry itself.

I had the same concern.... fan suddenly ramped up full speed while updating some apps in the App Store. It didn't seem normal because cpu wasn't working hard I resetted the SMC and so far no loud fan noise hopefully t stays that way.

seadragon said:

I'm just observing that the fan doesn't actually ramp up. It's like a light switch going from 0 to 6900 rpm instantly. Then in slowly backs down. Readings are from iStat Menus.

In comparison, my 2010 MBP fan is always on at a very low speed and the will gradually increase in speed when needed.

The thermal design and fan programming is probably different on the newer machines. The new rMBP seems to keep the fan off until needed.

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Maybe, I've yet to try one. A SMC reset may help as that algorithm is controlled by the SMC.

seadragon said:

What I've noticed with my new MBP compared to my old one is that the fan doesn't slowly ramp up. Instead, is stays off and then goes up to full speed, then slowly ramps back down.

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Mine does this too. It kind of scared me the first time it happened - I've never had a machine do that before. So...either it's normal, or both of our machines are jacked.

seadragon said:

I'm just observing that the fan doesn't actually ramp up. It's like a light switch going from 0 to 6900 rpm instantly. Then in slowly backs down. Readings are from iStat Menus.

In comparison, my 2010 MBP fan is always on at a very low speed and the will gradually increase in speed when needed.

The thermal design and fan programming is probably different on the newer machines. The new rMBP seems to keep the fan off until needed.

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Istat menu needs an update for the 2015" rMBP so i wouldn't read anything into any info that the current version of the app provides

I'm gonna chime in here because I have the exact same issue: My fan is at 0 (according to iStat) and staying there.

It freaked me out because I was using Chrome to view a video stream (yeah yeah, big mistake), and I noticed it was REALLY sucking up battery power (no big shocker there). Then coconutBattery popped up a warning that at 95°F (35°C), my battery was overheating. Yikes!

So I immediately quit Chrome, and the massive power drain stopped (32 watts down to 9.5 watts... wow). But I noticed that even after 20 minutes, the temps were only barely coming down, by maybe 1 degree. Finally I noticed iStat was showing the fan at 0 RPM, which gave me a panic attack.

Reboot, and my fan hits 1300 RPM... then drops to zero after 5 minutes. Reset the PRAM and SMC. Same thing. Sometimes the fan stays at zero even after the reboot.

Called up Apple tech support, and after doing the usual diagnostics dance, they have set me up for a genius bar appointment for Saturday.

Though, the rep I spoke to did inject a little sanity: My Mac hasn't shut down or KP'd, Apple diagnostics reports everything is all right, and my battery is charging up fine despite these supposedly high temps. He suggested that maybe these apps aren't reporting the right information, but that still getting the MBPr checked out at an Apple Store is worth doing.

Now that others are reporting the same thing, I'm wondering if maybe this is normal after all?

seadragon said:

That's exactly what I'm trying to determine too... Is it normal or not. I have one more week in my return window at the Apple Store.

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You realize that any "monitoring" type app likely needs to be updated for the 2015 rMBP with the broadwell chips. I know istat menus does and the dev said they are working on it so u also would not be surprised that an app like coconut battery does as well (I don't use this app).

seadragon said:

That's exactly what I'm trying to determine too... Is it normal or not. I have one more week in my return window at the Apple Store.

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I'm already past my return window, so I'd have to go the support route if there is a problem.

So, it's been an hour and a half since I started panicking. Aside from the reboots, the Apple Diagnostics run and a 20 minute shutdown which did nothing to lower the temps for long, this MBPr has been on the whole time. I'm posting on it now... still hasn't crashed or shown any other signs of distress, even as CoconutBattery tells me how close the battery temp is to max, and that my fan isn't running.

So... I'm guessing it's normal then. I'll just watch it carefully and hope it doesn't fry.

2015 13 rMBP fan activation

seadragon said:

Their website says it was updated for the new machines as of yesterday.

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Good find. Though I've been clicking on the check for updates button in the app for the past week and there has been no update pushed out. Looking at the main download link in their site it still says version 5.03 but the release notes has 5.1 listed so I suspect they have updated the release notes but have not yet pushed out the latest version yet. If you look in the istat menu setup screen for temperature sensors you probably still have only 1 or 2 sensors available like ssd and right fan but no sensors for cpu and everything else. That means you still have the old version.

seadragon said:

Thanks for your reply!

What I've noticed with my new MBP compared to my old one is that the fan doesn't slowly ramp up. Instead, is stays off and then goes up to full speed, then slowly ramps back down.

For example, in Lightroom, I select the option to build 1:1 previews for about 100 photos. The fan stays off until about the 15th photo. Then it comes on and instantly goes to full speed. After a few seconds is slowly backs down in speed then runs at a medium rate until the job is finished.

On my 2010 MBP, the fan slowly ramps up and then holds at about a medium speed.

The fan on the new one definitely works, it just works differently than what I'm used to.

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Actually, it does slowly ramp up. The reason why you think it suddenly ramps up is that it remains totally silent until around 4000 rpm or so. Then that's when the noise increases exponentially.

I use SMCfancontrol to monitor my fans.

2015 13 rMBP fan activation

seadragon said:

Ahhh... good find on your part too Diesel!



Yes, I just bought the app today and it is 5.03. I just automatically assumed it was 5.1 that I downloaded. You're absolutely right. They haven't released 5.1 yet. How strange. I hope it wasn't an April Fools thing!

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I just sent them an email asking them what was going on. I don't think it's an April fools joke as that would be very unprofessional on their part. Most likely a case of the update not being well coordinated (updating the site before actually making the update available).

My guess is that once we get the updated app it will show that the fans idle around 1000-1300 rpm like the previous rmbp and not at 0 as is currently being reported by the app.

seadragon said:

Great! Thanks for doing that. I'll keep checking for the update. I think you're right and that the 0 rpm is just a software glitch.

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The dev wrote back and provided a link to a download for a beta version of 5.1 (I assume it was a beta version since the link url had "beta" in it) but I told them that I was not interested in testing their product and if they had a final version then they should push it out. I am not going to risk any problems with untested software on my new 2015 rMBP. If you look on their version history site now, they've removed the April 1 date for version 5.1 and replaced it with "coming soon".

seadragon said:

Well, I've done the SMC reset a couple of times now and the fan is still acting inconsistently.

It jumps to full speed when exporting photos from Lightroom, but not every time. If I reboot the computer and do the same job, the fan might ramp up normally. Then another reboot and same job it jumps straight to full speed. Repeat sequence again and it works normally.

I'm just not sure if the fan sensor is working properly. I have a feeling it's letting the CPU get hot then it suddenly "panics" and runs the fan on full.

I'm might just return it but really not sure what to think at this point.

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How are you determining when the fan is running on full? By your own ears or by istat menu? If istat menu I think it's safe to say that the current version might not be accurate.

yjchua95 said:

Actually, it does slowly ramp up. The reason why you think it suddenly ramps up is that it remains totally silent until around 4000 rpm or so. Then that's when the noise increases exponentially.

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Normally, yes. Seemingly not the case with these new rMBPs.

In my limited experience of the 2015 13" rMBP, it does seem to do exactly as the OP is suggesting – the fan remains at close-to-idle speed until a certain thermal point where it INSTANTLY hits extremely high speed fans and ramps down slowly. Forget monitoring, you can hear it - in a big way.

I've owned a number of Macs, worked with even more, and I've never experienced this before. My only experience of the 2015 13" rMBP is of a friend's who bought one last weekend. The same behaviour described by the OP happened whilst importing all of his photos from an old Windows laptop.

FWIW, it happened twice within one sitting, without restarts. It was like flicking a switch, in terms of fan speed, as opposed to twisting a dimmer switch - if you will.