iMac performance slowly degrades to unusable while long queue of Handbrake transcodes

Discussion in 'Apple TV and Home Theater' started by knemonic, Feb 22, 2011.

  1. knemonic macrumors 6502a

    Jan 14, 2009
    Hey all,

    Curious if anyone can shed some light on a simple fix once in awhile to this.

    I am transcoding a large queue of movies, hundreds to be exact. The 5-10 or so I am still able to use my iMac with no issues, surf the net, reply to emails, even watch flash video and such.

    I have done about 23 now and now to minimize mail takes even a sec, webpages load slowly and in general performance is degrading.

    Is this a memory issue where it gets clogged can the only way to refresh the system is do a restart? I prefer not to do this since I will lose whatever transcode that is currently going on.

    Or is there a memory dump I can perform during this to help performance?

    I assume it has everything to do with the memory since it is non-stop transcoding, meaning it is full. I check Activity Monitor and it shows 3.79 of my 4gb of memory is being used. On average 95% of the cpu is being used as well, which makes sense.

    Any suggestions is greatly appreciated.
  2. McGiord macrumors 601


    Oct 5, 2003
    Dark Castle
    I don't know the answer to your question. I will expect the OS to adjust the memory allocation when you are trying to do other things, but it may depend on how Handbrake handles it.
    May be I am dead wrong.
    In the old days of MacOS you were able to define the amount of memory for the application in the Finder by get info. I have not checked in years as I have not needed, and I'm away from my Mac to look around.
    Hopefully some other members will have better answers.
    Quite interesting for me, as I have been procrastinating that Handbrake task.
  3. knemonic thread starter macrumors 6502a

    Jan 14, 2009
    Ya, I remember when they came out with Snow Leopard, there was speculation that they would include the memory allocation feature that was used in OS 9 based on the fact they brought back the Put Back option in the Trash can.

    I'll say this, I noticed the CPU % goes down for Handbrake when I hit the quote button in this thread to reply, meaning it is automatically managing the CPU from Handbrake to Safari.

    I honestly think this has a lot to do with memory though because mine is consistently full and went from 200mb like I said before to 27mb now that I have Safari. So the instant I open anything else, like Word, performance drops really low.

    Really what it comes down to is if Handbrake is actually using all that memory allocated or not. Hopefully I someone with system programming can shed some light on this.
  4. Hellhammer Moderator


    Staff Member

    Dec 10, 2008
    Are you getting lots of page outs? What is using your RAM? I would post this to HandBrake forums
  5. gnasher729, Feb 22, 2011
    Last edited: Feb 22, 2011

    gnasher729 macrumors P6


    Nov 25, 2005
    There are exactly two things that you can do to help with your problem: 1. Use a shorter queue. 2. Download the Handbrake source code, figure out how to solve your problem, fix it, send the changed code back to the Handbrake developers.

    On the other hand, Handbrake should use very little memory (maybe 20 MB) so maybe there is something completely different that is eating your memory.

    Your interpretation of this is completely wrong. Your memory is full. Whatever action you took causes a lot of paging to happen, your Mac is waiting for the hard drive, and therefore stops Handbrake. Handbrake itself runs and always has run at low priority so that other tasks are completely undisturbed by it.
  6. Omne666 macrumors 6502a

    Sep 16, 2010
    Melbourne, Australia
    I must admit that when ever I do a heap of ripping, within a couple of days I've basically got to restart my iMac as it slows to a crawl throughout the process.

    I've always attributed this to the ripping process, though the Activity Monitor doesn't seem to indicate anything untoward with HB. Its actually been worse since Snow Leopard came out. These days, even if I do just a few rips a week, I need to reboot to get my machine back up to speed within the month.

    My machine used to go for months on end with a restart.

    :D Time for an Upgrade!! 27" i7, here I come! :D
  7. brisbaneguy29 macrumors 6502


    Nov 27, 2007
    I have 2 of the 27' iMacs one with 8GB of RAM and one with 4GB of Ram. Now normally I would say 4GB of RAM is plenty, and especially seeing as 2 years ago that was a lot, but I notice a massive problem on the 4GB machine after a couple of days use, but the 8GB machine runs for weeks between restarts.

    I don't pretend to know anything about system RAM, or how it is used, but I do know that 4GB in the new 27" machines does not seem to cut it, where I would have thought it have been heaps. After about 2 days the page outs exceed the page ins and it needs a restart. On the 8GB machine the page outs never get over about 2% of the page ins. For example right now, ins= 268,018 and outs= 303, and i have used handbrake several times today. I have queued many movies one after the other, without problem.

    I have ordered more RAM from eBay for the 4GB machine because it just gets too slow too quickly. If you have one of the new iMacs I really suggest you get at least 8GB installed. It is dirt cheap on eBay.
  8. Omne666 macrumors 6502a

    Sep 16, 2010
    Melbourne, Australia
    Yeah...since Leopard, my 4 gig has seemed to be.......inadequate. LOL...and Im running the last of the white iMacs. Its was like a blast when I got it. 'sigh'....seems to remind me of the Windoze world where every OS update meant a hardware upgrade.

    Still, on the brighter side, I have a role for this beastie as a server of ATVs at another location. No ripping involved. Just waiting to see what the next iMac release brings before I upgrade.
  9. rayward macrumors 68000

    Mar 13, 2007
    Houston, TX
    I have an i7 (see sig.) with only 4 gigs of RAM. I plan to add more, but I do not think that it matters for Handbrake. My understanding is that HB is processor-intensive and, as a consequence, doesn't use much RAM. Adding RAM will help overall, but not make a lot of difference when transcoding. If you want to speed up Handbrake, you need a faster chip; plain and simple.

    As to the OP's issue, on my old PowerPC iMac I used to leave the thing alone when transcoding. Queue size didn't matter, I could be doing one (HD) transcode and the whole system would grind to a halt. Processor overload, I presumed.

    Also, on occasion, if I'd been trying to use the Mac the transcode would come out jumpy. This made no sense as everything is digital, but it only happened when I used the Mac and never happened when I didn't. The upgrade solved this, and I can now be transcoding a decent queue of HD movies, ripping a Blu Ray, tagging and uploading movies to iTunes - all simultaneously. Handbrake's processing rate may drop from ~23 to ~18, but that's what it's supposed to do.
  10. knemonic thread starter macrumors 6502a

    Jan 14, 2009
    Here is some detailed info. As you can see, Handbrake is taking a lot of the memory up.

    Attached Files:

  11. bearcatrp macrumors 68000

    Sep 24, 2008
    Boon Docks USA
    Definitely time to add ram. Rule of thumb is if page outs is 10% or more of page ins, then upgrade. SL was supposed to clear ram faster than previous versions but I haven't seen it. I have 8 GB in mine and when I get to where yours is at, I reboot. The slow hard drive is partially to blame for this too. One other thing. Are you using ONLY the internal disk? If so, suggest you use a scratch disk (external disk). This helps allot. Make sure it's a 7200 rpm too.
  12. knemonic thread starter macrumors 6502a

    Jan 14, 2009
    I have Handbrake getting the source from an external and saving back to the same external. I use the 3tb seagate hard drives, the main through firewire 800.

    I believe there is consensus around that I can upgrade my iMac to 6gb even though 4gb is the stated spec. So I may be able to add in an extra 2gb, but beyond that, I cannot afford to get a new system.

    The system does slow down, but not to a point I cannot use it, so this is not critical, I just thought there might be a solution to it, when really it is an inherent issue with SL.

    I am curious, how is the new GPUs out there playing a role in speeding things up? I know the Nvidia chipsets have h.264 built in, so I would assume encoding would be faster on those systems. I have a 11" macbook air, which has the 320m gpu, so I was curious if I might get a bit faster encoding abilities using that in addition to my iMac. Slower cpu and less memory, but I know they are putting a lot of emphasis on GPUs lately, I thought this may be something to try.

    Thank you so much for your help, very helpful!
  13. dynaflash macrumors 68020

    Mar 27, 2003
    Hmm, 1.41 GB of real ram is pretty steep for HB. HB will use more ram for higher rez input as it stores frames in memory for processing. So for example raw decoded Blu Ray will use much more ram than say a standard dvd. I was doing an encode yesterday on some 720p source material and HB was using about 340 mb of real ram. What version of HandBrake are you using ? Does the ram useage creep up the longer HB is running or does it stay pretty consistent ? What is your source material ?
    How hot is your Mac getting ? HB loves to eat up cpu and its possible your overheating as it runs longer. Its happened before. That said 1.41 GB of real ram is pretty high.
  14. dynaflash macrumors 68020

    Mar 27, 2003
    HandBrake does not utilize the gpu as the x264 encoder is hand crafted to get max performance from the cpu. So basically the gpu is ignored. HandBrake is all about cpu.

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