Have you ever wondered why your laptop’s fan is running loudly despite of relatively low CPU usage (like 10 to 15%)? Or your laptop can operate on battery only for couple of hours with such low CPU usage?If so, this posting answers why it happens and tell you what you can do to improve the situation.CPU Usage number can be misleadingIn the past, most laptops were equipped with single-core single-threaded CPUs and their structure was something like Figure 1. When program runs, most components in the system turned active as shown in Figure 2 (colored components are active). Once it is finished, the entire system returns to idle (power saving) state. So, the power consumed by the laptop was determined primarily by how long they become active. Hence, the relationship between CPU usage and power consumption was almost linear and looked like Figure 3. 1. Single CPU system configuration 2. 100% busy single CPU system 3. CPU usage vs. power consumption However, if your laptop is new, it probably has more than one CPU core and each core may support multi threading (also known as Intel Hyper-Threading Technology).

For example, dual-core multi-threading enabled CPU is configured as shown in Figure 4.best upright vacuum cleaners ratings Because all CPU cores/threads share the rest of the system, only one active CPU core/thread will keep most of the system active (in other words, high power consumption state) as shown in Figure 5.best cleaner for unfinished hardwood floors This means, if you are running single-threaded application and it keeps one CPU thread busy 100%, total CPU usage is still 25%, but most of the components in your laptop are active and consuming very high power already.best vacuum cleaner for ceramic floors

By increasing workload, more cores/threads will become active, but the power consumption increases only gradually because additional cores/threads are relatively small part of the system (Figure 6~8).best vacuum cleaner concrete floors As a result, the relationship between CPU usage and power consumption is not linear and looks like Figure 9.vacuum cleaner price bangladesh Power consumption increases very rapidly until the first core/thread’s usage reaches 100%. furnace and duct cleaning equipmentIn this example, it is when total CPU use reaches 25%. If you compare Figure 2 and Figure 5, you will notice that they are very similar situations (one core or thread is running 100%).

In fact, they consume similar amount of power. The only difference is, Figure 2 was called “100% CPU used”, and people accepted short battery life in the past. But, Figure 5 is now considered “only 25% CPU used” and people tend to think “CPU is not so busy, and it should not consume much power”. 4. Dual-core multi-threadedCPU configuration 5. 25% busy dual-coremulti-threaded system 6. 50% busy dual-coremulti-threaded system 7. 75% busy dual-coremulti-threaded system 8. 100% busy dual-coremulti-threaded system 9. CPU usage vs. Power Consumption So, what can you do? If most of the programs you run are (usually, most programs except for heavy games and image/video processing programs are single-threaded), you need to anticipate the CPU usage impact to the battery life can be aware that power consumption increases very rapidly as CPU usage number increases. Just a couple of percentage of CPU usage increase can easily decrease more than one hour of battery life.

To maximize your laptop’s battery life, you need to carefully monitor CPU usage and make sure that unnecessary programs are not wasting CPU cycles. You can monitor program activities with standard tools like Windows Task Manager, but they only tells you current snapshot. You will not know what happened while you are not watching at the tool window. Battery Life Maximizer shows the cumulative CPU time usage by each program. This will make it easy for you to find the program that is wasting CPU time on your laptop.References Intel: Frequently Asked Questions: Intel® Multi-Core Processor Architecture Intel: Performance Insights to Intel® Hyper-Threading Technology Filed in: TechBlog | • Page 1 of 2 • 12Fan runs all the time Last edited by boarder428 on Sun Apr 28, 2013 10:12 am, edited 1 time in total. Posts: 77Joined: Sat Jan 08, 2011 9:13 pmLocation: Eastern NebraskaAge: 43 Operating System: Ultimate Edition 3.4 64 BIT Re: Fan runs all the time

Way to narrow it down. Posts: 485Joined: Tue Apr 24, 2012 1:16 pmAge: 39 Operating System: Other Linux /us/gpudownload/l ... linux.aspxThe above is the prop driver... Posts: 1087Joined: Wed May 25, 2011 5:56 amLocation: IndiaAge: 31 Operating System: Ultimate Edition 3.5 64 BIT /drivers) and fill in the parameters...the usual stuff..radeon series, arch type(32 or 64) etc..Thanks, that's a very exhaustive procedure. Any easier way around it?EDIT: So I'm trying to figure out the correct path to take here? My card is listed as one that is supported by Ubuntu.I copied this off the ask ubuntu link supplied above. Last edited by boarder428 on Wed Apr 17, 2013 10:50 pm, edited 1 time in total. It is very thorough and may look exausting, but it covers everything. And once you get the hang of installing, it will take minutes to complete... Users browsing this forum: No registered users and 1 guest My MacBook (non-pro) Aluminum is a few years old.

Lately I experience the problem that my fans are running high even with moderate usage and the body really heatens up. It did this before, but only under heavy load (videos, flash or compiling of source files). Now it seems like a regular thing. I also have the comparison to another MacBook Pro, which is definitely not showing this behaviour, so I am quite sure that I am not imagining things. Also one night when I closed the lid of my macbook, fans would not stop running (it seems it did not go to sleep mode). Any Ideas what might be the reason? The only thing I can imagine is actually to open up the body and remove the dust from there with a spray duster. You should first determine if your computer is actually working harder due to some process(es) using a lot of CPU when they historically have not. Open the Activity Monitor app and check your CPU idle percentage. If your system is using a lot of CPU, the higher fan speed is likely justified. If you are consistently showing >90% idle, while your fans are racing, you likely have a 'mechanical' heat issue (such as dust/grime on heat sinks or some air blockage.)

If it IS a dust issue, I'd expect you would have noticed the fan gradually increasing its 'unloaded system' speed over time. There are also products that will let you monitor various sensors in your computer. Some will also let you control your minimum fan speed. My favorite is iStat Menus which has lots of options for what you want to watch and how you want to see it. It looks you have to clean the dust inside. This was the problem I had some time ago. Can recommend using free Macs Fan Control app to monitor fans speed, temperature sensors and to adjust fans speed. An SMC reboot will do the trick. I had the same problem after upgrading to Mavericks with my 2012 MBA.....here is a link to how to do it. We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed. So I have been having this problem for the last couple of weeks .

I finally fixed the problem and it was so weird I just had to post how I did it for you guys. I tried all the regular things every forum tells you to do such as: Reset SMC, Reset PRAM, Ran Diagnostics, Cleaned the fans and heat sinks, Changed power cords ... nothing worked. I downloaded iStat Menus I saw that CPU PECI Die was running at 300 degrees Then I noticed my CPU usage bar would just to 101% and every time that happened a process called CUPSD was activating. So I googled CUPSD and found out that its a wireless printing protocol. So I went into System Preferences / Printers and deleted all the printers I added the printer I use regularly again And VOILA, The temp on the PECI die went down to 91 degrees and the process stopped happening. Weird but it worked! Same problem - my finding was a small cotton ball of fiber stuck at the vent of the fan. I obviously had to open the back of the laptop, but it was pretty easy if you have the right screwdriver heads.

I tried Activity Monitor and couldn't find a culprit there. I didn't think my fan was getting dirty, but only did it in the end because I ran out of other options. found the problem :) I had a similar problem with the fan running at high speed all the time. I opened up Activity Monitor and discovered that the "Dashboard" app was taking up some 60%+ of CPU. I deleted all the windows in the Dashboard and the problem was solved. So clearly I and perhaps others need to be judicious in their use of Dashboard Apps. May solve other people's problems also. I had the same problem where my fan was running on high virtually the entire time I was using my Macbook Pro (mid-2014), and found this site. After looking at the posts here I decided to check the Activity Monitor, and for me, it wound up being Google Chrome. The Chrome Helper processes were many, and multiple instances running at the same time. After trying (unsuccessfully) to stop each process (they would come right back each closure), I closed Google Chrome completely and the fan stopped running.

Using Safari only, I am not experiencing this problem (so far), and the computer is running much cooler. It looks as if I'll stick with Safari exclusively as my browser. I can't thank you enough for the info here. I hope this contribution helps others also. On My MacBook Air, my fan was running like hair dryer. Checked up Activity Monitor window and saw that a HP printer process was running with 300% CPU utilisation. Realised that, half an hour back, i sent a print command to a HP Inket Jet printer (but had not connected the printer yet on USB). Instead of killing the process, I connected the Printer. After the printout was over, I could see on the Activity monitor, that in around 30 seconds, the CPU was back to normal. Not sure, it is HP Driver issue or not? If there is something spooled for printout and the printer is not connected, it must be the bad driver that still tries to use CPU to find out the PRINTER for end less time. Ok, I had the same issue suddenly and I was going crazy.

What fixed it for me. 1. Opened the back case while MBP was running. 2. Blew on my high speed fan (due to my blow it stopped and started again) ha, then within milliseconds to seconds it came back to life - normal fan speed. So my verdict, the fan controller app might have "stuck" so it needs a "manual" reset. Once again, just blow the fan while powered on. I would definitely open activity monitor (Cmd+Space then search Activity Monitor) and go to CPU, then look at what is using the most. Mine was Microsoft Outlook using approximately 250% of CPU. Closed it, fan immediately turned off. If it is a program you use all the time, try finding an alternative and see if it works better. I wanted to say that this discussion saved my life. I've already tried to do PRAM and SMC reset with no success. After reading the postings I identified my HP printer was taking 388% of my CPU. Then I've searched on how to shut it down (it was not working on the activity monitor) and found this post:

After doing that my CPU went back to normal. My Apple MacBook Pro, my fan would not stop running and the battery was running out very quick. I spoke to the Apple Technicians who could not sort out the problem. Checked up Activity Monitor window and saw that a HP printer process was running with 340% CPU utilisation. I went to System Preferences - Printers and Scanners and realised that there were 3 printers connected to it. Once I deleted the redundant printers, the process stopped running and the fans stopped running. Thank you to this Google search! Same problem here, on a 2009 MacBook Pro 17" - fans running insanely fast and the underside was too hot to have on my lap. The battery is 7 years old and ready for a replacement soon, so I thought it might be related. Otherwise the machine is still fantastic. Checked Activity Monitor and the Finder CPU usage was always maxed out, never below 98% whenever I had a window open. More windows just crippled the running speed of the machine.