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Punch Card
Posts: 1
Registered: ‎04-10-2010
Location: Denmark
Message 21 of 150 (4,277 Views)

Re: Ideapad U350 - excessive fan noise

Hi guys,


I also own a U350 with excessive fan noise.


Just while reading in this forum and occasionally scrolling to read the posts the fan goes on and off (between 38 and 43 degrees).


My machine has the Pentium SU2700 , 1,3 ghz single-core cpu and 3 gb ram. But I noticed that no matter which power scheme I choose it never throttles to anything less than 1,2 ghz. That does not seem right to me. So it is either 1,2 or 1,3 ghz. My old laptop typically throttles down to 600 mhz (from 1,4) and even my workstation (non-laptop) goes from 2,8 ghz to 800 mhz.

But maybe that is just my cpu that can't do anything else - although it does support SpeedStep.


If it was possible to throttle it down to for instance 600 mhz that should save some heat and power I would guess :-)


Also note that I have tried both Vista HP 32 bit and Windows 7 HP 32 bit - they both have same behaviour regarding fan going on and off very often.


As already mentioned, the solution should be to increase the temperature threshold where the fan starts. On my machine it is 43 degrees - it would be nice if it was 55. Or maybe a mode where the fan spins extremely slowly and inaudible.



Punch Card
Posts: 19
Registered: ‎03-19-2010
Location: United States
Message 22 of 150 (4,267 Views)

Re: Ideapad U350 - excessive fan noise

[ Edited ]

sme, I believe that's the correct behavior for that chip.


My SU4100 also acts the same way. The processor runs at 1.3ghz 1.0v when it's loaded, and 1.2ghz 0.9v when it's idling. I have found no way of underclocking/undervolting unfortunately. I am not sure why intel was not more aggressive when applying speedstep, but maybe they found the power usage at idling is already low enough.

Punch Card
Posts: 14
Registered: ‎03-09-2010
Location: NYC
Message 23 of 150 (4,218 Views)

Re: U350 - any solution to the fan noise problem? (win 7 x64)

Sorry for the double post; unsurprisingly, they are a few threads talking about this problem, and I posted in one of the other ones. 


If you recall, when I called tech support, they claimed they knew about the problem and could fix it. Skeptically, I sent my U350 to Lenovo, so they could do their magic. It came back very quickly. That's because they didn't do anything. They didn't even open it up. They just enclosed a poorly written message that contradicted what the phone tech guy said:


"Talk to engineer and find out it's normal fan runs all the time. It designed to avoid overheat issue."


Lame. So the fan really is supposed to be running at full speed most of the time, huh? I forgot how bad it was. On the weekends, I do some work at group studio space that's supposed to be pretty quiet. I'm actually getting complaints about my laptop's noise. I wish I could get my money back and buy something else. This has been a major disappointment. I'm hoping a BIOS fix comes through; if not, I guess I'm going to have to sell it and start over. Option B is to open the thing up and disconnect the fan.




Punch Card
Posts: 14
Registered: ‎02-24-2010
Location: Sweden
Message 24 of 150 (4,123 Views)

Re: U350 - any solution to the fan noise problem? (win 7 x64)

Hi Mark,


Count me in, i am today a proud owner of a S10, but looking to get a U350, however, i am NOT interrested if i risk getting those kind of issues, i waited with the S10 til the fan noise was solved.

I love helping people, support engineer.
Punch Card
Posts: 7
Registered: ‎04-17-2010
Location: Brazil
Message 25 of 150 (4,019 Views)

Re: U350 - any solution to the fan noise problem? (win 7 x64)

I also have the Fan noise issue. This is my second Ideapad U350, I returned the first because I thought that something was wrong with its fan. While waiting for a new U350, I found this. The fan noise pisses me off when I get to the library or any other silent place. Also, the fan kicks up even when the computer is idling. My CPU temperature is constantly around 39 to 42 degrees (C) and the fan speed changes all the time. Normally I use the U350 when studying and the variation of fan noise breaks my concentration all the time. I also suspect that the fan speed constantly at full is eating too much battery. With Wireless off and brightness at lowest, Win7 says that I have more than 8 hours of battery left. As soon as the fan begins to spin at full, my estimated battery time goes to around 6 hours. This is with a 4cell battery and without doing anything at the notebook. Lastly, I have two other rants that make me think if I should return this second Lenovo U350 and pay $150 more to get an Asus UL30: - The BIOS is severely crippled down. I can`t set the FSB, can`t set fan speeds, can`t set Hard Disk acoustic mode, can`t set anything that was available at my last Dell Vostro 1400 notebook. - Can`t change the FSB using SetFSB. I used to do this to lower my FSB speed on my Dell while I was working with light tasks, an action that increased my battery life from 2:30h to 4:00h. Altough the U350 uses the same clock generator as the S10 (SLG8SP513V), the FSB speed can`t be changed by SetFSB as the speed seems to be locked by BIOS when the computer initializes.
What's DOS?
Posts: 4
Registered: ‎04-08-2010
Location: USA
Message 26 of 150 (3,920 Views)

Re: U350 - any solution to the fan noise problem? (win 7 x64)

So is there going to be a response from a Lenovo Moderator, or do we just have to keep complaining?  Everything about this computer is extremely appeals, but the fan issue is a deal breaker.


Mark, any updates?

Paper Tape
Posts: 8
Registered: ‎09-10-2009
Location: CA
Message 27 of 150 (3,838 Views)

Re: U350 - any solution to the fan noise problem? (win 7 x64)

I have two U350s ... one with the SU2700 and one with the dual core SU7300.   On the SU2700, the fan almost never shuts up. On the 7300, it can be quiet at times if I am not doing anything, slow down the cpus and set the cooling to passive in Win7. But the fans usually kick on loudly when I am doing anything non trivial (like surfing the web?).  


I have also noticed that while charging the fans are much more likely to be going full blast but that is understandable. The large battery does get warm.


In linux, I have almost no control over the fans so the problem is much worse. 


I have ripped apart both of them going down to the cpu, scraping off the rubbery material between the chips and the heatsink and putting on some good quality silver-based thermal grease.  There are also a bunch of useless paper stickers everywhere around the heat sink which I have removed. On the SU2700, this helped a LOT in cutting down fan nosie but I still wish I had more control over how the fans run.


A lot of times I would really love to be able to almost cripple the CPUs to a crawl if that meant the fan wouldn't be coming on.


My suggestion would be to have somewhat of an API and SOME way to give users the ability to control the fan. I understand at some point the fan HAS to be on at full blast and sometimes you HAVE to shut down if things get too hot. But having this "fan is always on whether you like it or not" is very annoying to someone like me who wouldn't have any trouble picking from 4 or 5 different settings to customize things a bit more.

Paper Tape
Posts: 1
Registered: ‎04-22-2010
Location: Finland
Message 28 of 150 (3,732 Views)

Re: U350 - any solution to the fan noise problem? (win 7 x64)



Another user here frustrated in the U350 fan noise, 2 days after purchase and beginning to hope I hadn't bought it.. I have an SU2700 with Vista HP, the fan is almost constantly on. Please Lenovo, release a new BIOS or do anything that fixes this flaw..!

What's DOS?
Posts: 1
Registered: ‎04-23-2010
Location: Denmark
Message 29 of 150 (3,635 Views)

Re: U350 - any solution to the fan noise problem? (win 7 x64)

Hi Mark,


Thank you for your updated reply. I have the same issue as other customers, who have bought the U350. My fan is constantly on, and it starts up only a few minutes after Windows 7 has finished loading. It is frustrating to listen to, and the battery doesn't last that long, when the fan is always on!


My laptop has been sent in via your RMA system, and no errors were found on the laptop - then fan was replaced, which, of course, didn't solve my issue.


Afterwards I called the tech support in Denmark, and they asked me to write to the head of support on the following adress: That mail was sent on 30. march 2010. I have called the tech support twice afterwards, and recived message, that my issue has been taken to a development team in UK, where they prioritize the incoming requests. Last time I called was 15. April, and still I haven't heard anything new in this matter.


I'm still optimistic, but I sure hope to hear from Lenovo very soon! If you wish to get my RMA number, please don't hesitate to contact me!


Best regards



Mark_Lenovo wrote:

Ugh, RocketJeff,


There has been a fair amount of fan discussion in the forum - most on the S10 netbook, and then the G550 systems, but I've heard a few comments on the U350 and have relayed to our engineering team.


Let me try to explain and set some expectations about this....


1) In general, we have communicated this back to Idea and Valueline development teams as a broader "lesson learned" to be considered as new models are developed.  Specifically that many customers have a sensitivity to fan behavior and that fan operation needs to progress from one speed to the next, rather than jumping from off / low to maximum speed if the CPU temp suddenly spikes.  We've also suggested that there be some wider separation in the temp range for the fan stepping - 4 or 5 degrees seems tight, and after the unit warms up can lead to cycling of the fan.  This would generally be considered as new models are developed, and potentially as an update for some existing systems, in a future bios release.


2) As all potential changes require engineering time and development expense for testing, a clear case for a model specific change is required to obtain a specific BIOS update in the near term.  Generally, it is easier to build a case for immediate action when there are a compelling number of customers with the product, and voicing similar concerns.   At this point, it may be more difficult to seek an specific BIOS release based on the experiences of three or four customers on the U350.   I'm not discounting your opinions - I do appreciate them, and will follow this discussion as others join and a consensus is formed.


I'll try to go through the forum, and combine discussions on U350 fan behavior so that we can have a clearer view on the number of customers interested in this topic and see what we can do to move forward on the issue.


Best regards,




Paper Tape
Posts: 3
Registered: ‎04-24-2010
Location: Ohio
Message 30 of 150 (3,598 Views)

Re: U350 - any solution to the fan noise problem? (win 7 x64)



I just bought a brand new U350.   I have the fan noise issue also.  Once the fan starts running, it never shuts off.


I turned off AERO, un-installed many startup programs, sql server, services, and put it in the Power Saver mode.


I now have the U350 down to 0% CPU when idle (in task manager) and the FAN IS STILL RUNNING and never shuts off.


My CPU temps are at 32degC, and system at 40C.


A notebook with 0% load should not have a fan running. This just doesn't make sense no matter how you look at it.  


Of course the fan should kick in with lots of load, but in the case of the U350, I believe that once it kicks in, it never shuts off.   I have been using notebooks for 20 years, and this is the first one where the fan behavior does not make sense.

Thank you



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