Nehalem Mac Pro systems suffer audio-based performance issues

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  • Reply 21 of 28
    emig647emig647 Posts: 2,416member
    Quote:
    Originally Posted by pondosinatra View Post


    It seems like Apple's QA testing over the past couple years has gone into the toilet - all I know is they can have my pre-metal (and non-glossy) 24" iMac when they pry it out of my cold, dead hands!



    Of course it has, they've had to use everyone for the maxipad, iphone, and ipods. It's becoming apparent more every day, Apple doesn't care about their computer side.



    Either way, I have slightly noticed these issues. I have a 8 core 2.66, and I'm usually idling around 38deg Celsius (normal), after a full work day my computer is around 54deg, and if I get after it and max out the cpus from compiling or encoding I can get it up to 65deg. I play iTunes all day long.



    I have a temp. monitor. With just iTunes playing I can get the northbridge up to a scorching 65deg Celsius. It seems the Northbridge heats up the most, so it's definitely more of a driver issue.



    I don't see them ignoring this situation forever. The new cpus will be based on the same northbridge drivers, and they'll have to correct those. Perhaps a 10.6.3 update? Either way I have yet to update to 10.6.2.



    Not to derail the thread, but the other issue they completely overlooked was itunes / quicktime crashing when returning the 2009 mac pro w/ ati 4780 back from sleep. I heard snow leopard corrects this, but still. Either way, I don't think the problem is as bad as these media sites are making it out to be.
  • Reply 22 of 28
    i386i386 Posts: 91member
    I haven't seen this at all on my system (using Mac Pro 2.66Mhz dual xeon 2009) . Sounds very much like a CODEC issue with either mp3 or AAC files. Has anyone tried different encoded MP3 and AAC files

    to see if there is any difference ? Does the issue happen in quicktime too ?



    The problem doesn't seem to be defined clearly enough to solve.
  • Reply 23 of 28
    docno42docno42 Posts: 3,348member
    Quote:
    Originally Posted by BenRoethig View Post


    Doesn't EFI just run a BIOS emulation?



    No. EFI is a replacement for BIOS. On PC's EFI can emulate BIOS for OS's that don't support EFI directly, but Apple doesn't (as they have never used nor relied on BIOS).



    http://en.wikipedia.org/wiki/Extensi...ware_Interface
  • Reply 24 of 28
    docno42docno42 Posts: 3,348member
    Quote:
    Originally Posted by emig647 View Post


    Of course it has, they've had to use everyone for the maxipad, iphone, and ipods. It's becoming apparent more every day, Apple doesn't care about their computer side.



    Yes, because Apple is completely incapable of focusing on more than one device at a time. Never mind they all use the same core technologies and have benefited extensively from the cross-pollination between categories.







    What a load of rubbish. I don't know why so many are threatened by Apple's success in area's other than the Mac - if you think Apple is going to abandon the Mac or make dramatic changes to the Mac experience you are seriously delusional.



    Having said this, it is annoying that simply playing iTunes can spike my Mac Pro's CPU temperature - but it doesn't seem to be dangerous or adversely affect the CPU's. I have thought about getting something like SMC fan control and bumping up the low speed thresholds for the fan's, but honestly it hasn't shown itself to be a significant issue.



    I do want to google around and see if there is an explanation why CPU A is routinely about 20% hotter than CPU B. Probably has to do with it's placement in the case and airflow since the CPU's are in-line. That was a nice thing about the G5's - they were staggard - but then again if they weren't they probably would have melted
  • Reply 25 of 28
    emig647emig647 Posts: 2,416member
    Quote:
    Originally Posted by DocNo42 View Post


    Yes, because Apple is completely incapable of focusing on more than one device at a time. Never mind they all use the same core technologies and have benefited extensively from the cross-pollination between categories.



    First of all, it was widely known that leopard was delayed because of the iPhone. Same technologies does not mean the same thing. Just means the same basis.



    Quote:

    What a load of rubbish. I don't know why so many are threatened by Apple's success in area's other than the Mac - if you think Apple is going to abandon the Mac or make dramatic changes to the Mac experience you are seriously delusional.



    It's already happened on more than one occasion. If their market took a shift towards smaller devices, that is where their attention will go. Many companies do this and often paint themselves into a corner. Apple will go where the money is.



    BTW that line that you quoted, was supposed to be half joking. But it is apparent they have been ignoring major issues on their computing side (or all sides) for many years. Security holes take forever to get patched, OS problems take forever to get fixed, seems each computer they release has some sort of issues that go wrong with it (small or major) and they take their sweet time getting to it (if they ever do).



    Quote:

    Having said this, it is annoying that simply playing iTunes can spike my Mac Pro's CPU temperature - but it doesn't seem to be dangerous or adversely affect the CPU's. I have thought about getting something like SMC fan control and bumping up the low speed thresholds for the fan's, but honestly it hasn't shown itself to be a significant issue.



    I do want to google around and see if there is an explanation why CPU A is routinely about 20% hotter than CPU B. Probably has to do with it's placement in the case and airflow since the CPU's are in-line. That was a nice thing about the G5's - they were staggard - but then again if they weren't they probably would have melted



    I will point out something I haven't seen very many sites point out. It's the northbridge that gets hit hard with the heat. Seems the northbridge almost goes up in heat immediately and takes cpu A a while to get there. I think this is more of a northbridge problem than anything else.
  • Reply 26 of 28
    OK -- here's my test results for running on my Mac Pro (early 2009 model) 4-core 2.66 GHz Nehalem computer.



    I ran two tests.



    Test 1. Ran HandBrake to encode two BBC Rough Dimand DVD series to Apple TV format using HandBrake defaults.



    Test 2. Same as 1 except I had iTunes playing audi files during the HandBrake execution.



    The HandBrake execution was consuming 70% of all my core's CPU cycles and core temps all climbed to around 200 to 206 deg F. Power consumption was at around 95 watts for the CPU/Processor.



    Test 1 completed in 3,685 wall time seconds



    Test 2 completed in 4,272 wall time seconds



    Difference in walltimes was 587 seconds.



    Test 2 was slower than Test 1 by approximately 16%



    I should run Test 1 several times to understand what its walltime variation would be -- but at this point it does seem that iTunes playing audio files is somehow influencing the likes of HandBrake execution performance.



    The HandBrake is very parallel and will consume as many threads as the computer provides and it's very CPU intensive.



    The iTunes CPU use is minimal so should not impact HandBrake running alongside it and in addition HandBrake leaves around 30% of my CPU cycles for other processes to use. So on the face of it the iTunes and HandBrake, from a CPU use standpoint, should not interfere with each other. That leaves at least two other resources or features that could be influencing the interaction between iTunes and HandBrake.



    One would be memory bandwidth contention. Is iTunes and HandBrake fighting over the aggregate memory bandwidth and slowing each other down ?



    Another thought which has been voiced/mentioned elsewhere is that somehow the Intel/Nehalem turbo boost is not being allowed to accelerate Handbrake's use of the cores but disallowing the cycle times to be increased from 2.66 GHz to 2.793 GHz, then to 2.926 GHz and finally 3.059 GHz.



    I find it of interest that the increase from 2.66 GHz to 3.059 GHz is 15%.



    The difference between Test 1 and Test 2 is 15.93%



    So, could the HandBrake degraded performance be supported by iTunes not allowing the turbo boost feature to favor/help HandBrake complete faster?



    At this point I'm apt to say this issue is not bogus and Apple needs/should in all fairness explain to Mac Pro (2009 models) users what is causing this. I suspect it may be a fact of life and we have to live with it -- but then on the other hand Apple may have a fix for this.



    Hmmmm ---- interesting...
  • Reply 27 of 28
    blastdoorblastdoor Posts: 1,973member
    looks like this affects me, too. I tried out the scenario they describe and I get exactly the same result.



    It certainly is weird and I hope that they fix it, but I can't say I've ever even noticed the issue prior to seeing this story, so I'm not really suffering here.



    I have a much bigger gripe involving what appears to be a bug in the Finder that was introduced sometime after 10.6. It basically prevents me from using utilities like rsync, and that really sucks.
  • Reply 28 of 28
    Quote:
    Originally Posted by Blastdoor View Post


    ...It basically prevents me from using utilities like rsync, and that really sucks.



    That's because they want you to use iSync instead
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