How to tell when you need more memory?

Discussion in 'Mac Pro' started by usna92, Oct 31, 2018.

  1. usna92 macrumors member

    usna92

    Joined:
    Mar 16, 2011
    Location:
    Seattle
    #1
    I currently have MP2010 with 2 x 3.33 GHz 6-Core Intel Xeon, 32GB Ram at 1333MHz, and a RX480. I was wondering if there was any value in upgrading any of the major components here CPUs, RAM, or video card. This is mostly a development machine, with some video processing (iMovie) not Final Cut Pro (yet). I am interesting in learning to use photoshop, but not quite there yet. I was looking at what is most likely the limiting resource and I was thinking memory, but being able to determine whether or not you need more memory is difficult. What methods are people using to determine that?
     
  2. AliGT83 macrumors member

    Joined:
    Jul 17, 2018
    #2
    After a day of normal use, open activity monitor, open the memory tab and then at the bottom look for swap used. If it says 0 bytes you never used all of the installed ram. If the value is higher I would consider start adding ram or at leasts fast SSDs on a pcie adapter so the penalty for swapping is less noticeable.
     
  3. pl1984 macrumors 68020

    Joined:
    Oct 31, 2017
    #3
    I'm in agreement with AliGT83 with one exception. I would recommend opening Activity Monitor while you're performing your work. You want to look at the memory pressure section. It's fairly intuitive in what it's telling you but if you need assistance with interpretation just ask.

    I noticed you did not mention an SSD. I would recommend installing one, even if it's a SATA SSD in one of the Mac Pro's standard hard drive slots. Development involves a lot of random disk I/O and an SSD should make a noticeable difference in your compile times (as well as other areas). Activity Monitor can also help you with disk usage.
     
  4. kohlson macrumors 68000

    Joined:
    Apr 23, 2010
    #4
    What @pl1984 said. SSD for sure. Unless you are working with lots of VMs, or very large images, it's unlikely more RAM will help. But Activity Monitor will show you. But if you hit swap with a spinning disk, you'll know it. Since SSDs are very resistant to shock and vibration, just install it in the lower optical bay - no need to attach it to anything other then the SATA cable.
    Note that 10.14.1 has support for NVMe drives (much faster SSDs on the PCIe bus). There's a separate thread in the Mac Pro forum on this.
    If you're doing any external disk read/writes, consider a USB3 card. They're cheap, too. Also a separate, sticky thread on that.
     
  5. orph macrumors 68000

    orph

    Joined:
    Dec 12, 2005
    Location:
    UK
    #5
    yep just like AliGT83 says keep activity monitor open, check it now and agen and see if you have large number's in "swap used"
    Screen Shot 2018-11-01 at 12.37.54 pm.png
    only thing id add is small amounts of "swap used" is ok but large numbers are bad, also if you can check it as you do tasks you may want to be faster to see what is going on, if your working and it's slow check activity monitor and see whats maxed out.
    Screen Shot 2018-10-12 at 4.44.49 pm.png
    thats an example of me exporting video, you can see the GPU is about 40% used and the CPU is hitting about ~700% (the app has two main processes going each using about 350% ie 3.5 cores so 700% total) which means it's CPU limited not GPU limited ram use is low only ~4GB live ram for the program/processes but id gess more cached in ram.

    osx by default will now cache as much as it can in to ram so memory used is not a good measure of ram use & now will when running low on ram start compressing the contents of the ram before it starts hitting the "swap" hard which is relay cool.

    iv got 32GB of ram and 99% of the time in CPU limited now at peak use times like exporting video etc..

    edit the video is 4K h264 export with some effects added, so use of GPU/CPU can change but mostly that screen shot is a good example for my exports
     
  6. pl1984, Nov 1, 2018
    Last edited: Nov 1, 2018

    pl1984 macrumors 68020

    Joined:
    Oct 31, 2017
    #6
    While the swap advice given by AliGT83 and orph is correct I would recommend ignoring the swap number and look at the "Memory Pressure" graph. It will be green when memory is plentiful, yellow when its nearing exhaustion, and red when there's insufficient memory. It graphs it over the "Update Frequency" so you can see a history of memory usage.

    Memory Pressure is Apple's way of representing memory consumption in a simple manner. Swap is useful if you know what swap is and how to interpret the value provided.
     
  7. orph macrumors 68000

    orph

    Joined:
    Dec 12, 2005
    Location:
    UK
    #7
    yep red is RAM upgrade time some yellow is optional, all yellow is upgrade time maybe, iv only seen my ram max out in AE
     
  8. usna92 thread starter macrumors member

    usna92

    Joined:
    Mar 16, 2011
    Location:
    Seattle
    #8
    I am running a 1TB SSD on a PCIe card for the boot drive, so I have the SSD side covered. I will look for the memory pressure part, as well as an eye on swap. I seem to max it out the most when working in handbrake, so I will see what the numbers look like there.
     
  9. AidenShaw macrumors P6

    AidenShaw

    Joined:
    Feb 8, 2003
    Location:
    The Peninsula
    #9
    This is good advice, but it misses an important factor.

    Systems use "free" memory to cache filesystem meta-data and data.

    In essence, if the system has free memory space, it will transparently move directory and file data into what is more or less a "RAM disk".

    Looking at swap and memory pressure data might not show you that a lot of performance is lost because there's no free (or "standby") RAM available for filesystem caching. Right now my Windows laptop shows:

    cache.jpg

    In other words, it shows about 16 GiB of RAM in use, and about 16 GiB of filesystem data in cache as "standby". So 50% of RAM is dedicated to active programs, but 100% of RAM is actually "in use". ("Standby" RAM will immediately be given to any program that asks for more active memory - so it is "available" according to this chart.)

    I'm not sure if "Activity Monitor - Memory Pressure" reflects that there isn't RAM available for filesystem caching - but if it doesn't you might see "green" when in fact additional RAM could really speed things up by increasing the effectiveness of filesystem caching.
     
  10. ssgbryan macrumors 6502a

    ssgbryan

    Joined:
    Jul 18, 2002
    #10
    The easiest way to tell if you need more memory - Are all 8 slots filled with 16Gb Sticks?

    If No - then you need more memory. :p
     

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9 October 31, 2018