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Fan Speed Burst?

W

wexford

macrumors member
Original poster
Nov 30, 2007
37
0
white 20" 2.16 core 2 iMac. had it about 3 weeks - got it brand new.

i was browsing the net, nothing intensive...

fan speed took off, sounded like a jet engine for 5-6 seconds. CPU fan was up around 2,600rpm - then backed down slowly and returned to normal.

any clue as to why that happened?
 
Flash if you're browsing the internet.

It'd be a little easier to diagnose if you watch your processes with Activity Monitor.
 
gotcha.

the only other thing (besides safari) that was running was realplayer, which i had installed about 2-3 minutes earlier.

it didnt seem like my cpu was working hard at the time of the burst, but i could be wrong.
 
To be honest, starting a thread on a forum about a computer issue is the last thing I normally do. For your fan burst situation I would do the following.

1. Open Activity Monitor (Or Terminal) and sort processes by CPU usage
2. Open Console and view the system logs
3. IM my colleagues
4. If we can't figure it out then I'd start a thread
 
Eidorian said:
To be honest, starting a thread on a forum about a computer issue is the last thing I normally do. For your fan burst situation I would do the following.

1. Open Activity Monitor (Or Terminal) and sort processes by CPU usage
2. Open Console and view the system logs
3. IM my colleagues
4. If we can't figure it out then I'd start a thread
Click to expand...

my knowledge base for this sort of thing is likely inferior to yours... and i'm not surrounded by any colleagues that are into computers... and i didnt have time to open the activity monitor, as it only lasted for a few seconds. but i'll try and do so if it happens again. the advice(?) about the system log is appreciated... thank you!

also, fyi, before posting, i had done a search on the forum for this problem, and it did seem like a few people have had this happen and were also curious to it's cause. so i thought i'd give a specific thread a shot...

again, thanks for the time.
 
Thank you for taking my advice into consideration. You might want to keep Activity Monitor open while web browsing to see if you can replicate the fan burst again.

iStat Pro or Menus would let you more easily set up a CPU usage history graph that's a little more accessible. :D

I'm glad to be of any other help.
 
wexford said:
white 20" 2.16 core 2 iMac. had it about 3 weeks - got it brand new.

i was browsing the net, nothing intensive...

fan speed took off, sounded like a jet engine for 5-6 seconds. CPU fan was up around 2,600rpm - then backed down slowly and returned to normal.

any clue as to why that happened?
Click to expand...

I do not think it is any think to worry about unless you suffer repeat incidents. I keep my iMac's fans boosted to keep the temps down. I use smcFanControl to do that. Also I noticed that the built in wireless generates a lot of heat so I keep that off and use a direct wire for networking.

Currently the only things I hear are the external drives spinning up when I use them.

Good luck with your hunt.
 
When I had a white iMac it used to do that sometimes too spin to max speed then slowly come down to normally again.

Never found out why never really bothered :)
 
vansouza said:
I keep my iMac's fans boosted to keep the temps down. I use smcFanControl to do that.
Click to expand...

I do this on my Macbook; it's a great way to keep the temperature under control, and within a steady range (48-51 deg. most of the time).
 
CD 1.83 mini also w/occasional fan speed bursts

I also occasionally have random fan speed bursts, on my 1.83 Core Duo mini.

When it happens, I haven't been able to localize a cause, but I've only caught it once or twice with iState Pro and Activity monitor open. In short, based on temp readings and CPU usage, I can find no reason for the random speed bursts.

On another thread, someone suggested the fan bursts could be responses to excessive heat caused by the GPU, and possibly in relation to Java usage...but, I can't attest to this with any certainty, at all.

The random fan speed burts might just be a "quirk" on some Macs. Personally, I just want to make sure the random fan speed bursts aren't indicative of an underlying larger problem...
 
fan bursts

i noticed the fan burst phenomenah happening afer changing the cpu multiple times, but it is probably not related.

did anyone else make hardware mods.

specifically, i went from stock 1.66ghz cd to 2ghz c2d to 2.16ghz c2d then back to stock 1.66 ghz cd. The problem seemed to occur after, but not immediatly after reverting to the 1.66 ghz cd processor.

when i backup my system, i intend to do a complete os load, but believe the problem to be unrelated to os.

also, sometimes, it would stay running at high speed (jet engine) continuously until I pushed power button to place the system in sleep.

best, tom
 
I was working on a dual 2.4 (give or take, it might be 2.5ish) Ghz PowerMac G5 and was in FCP with a single clip open in the timeline and as I drug the playhead back and forth, I found I could literally control the fan speed. The faster and further I moved it, the more they revved up. Quite fun and I didn't need to download a controller to do it!
 
1.83 CD Mac Mini

I really never was able to resolve/identify the problem, on my end. But, it never seemed to be a huge problem, just a quirky occurrence.

When the fanspeed bursts occurr, the fan RPMs go from a normal range of 1300-1600, to over 2000...all of a sudden, the mac mini sounds like vacuum cleaner.

In my case, I noticed the occasional fanspeed burst two months after first getting the mini, and over a month after I upgraded the RAM to 2GB. I don't think the upgrade has/had anything to do with the fan speed bursts.

After starting this thread, I haven't had any more fan speed burts occurrences (that I've seen). Go figure...

As noted in this and another thread, fanspeed bursts MIGHT be related to an over-worked/over-heated GPU for whatever reason (some thread mentioned JAVA causing this).

Try and note exactly what you're doing, what applications are open, just before/as the fan speed bursts occur. How often are yours occurring?

In any case, good luck!
 
Oh and I forgot to mention:

Any flash/java based websites max out my processor (G4 iBook, 1.42 Ghz, 1.5GB, Leopard) and run the fan(s) hard. The biggest culprit that I've narrowed it down to is YouTube. Its horrible on my computer, so if you have any of their videos playing and your fans kick in, this is probably it. Open activity monitor and see if Safari/FX is running the proc at max. I think flash cartoons etc do this also to my laptop.
 
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