will more memory help a heavy proccessor load ?

Discussion in 'Hardware' started by chiguy, Dec 2, 2005.

  1. It would seem to make more sense to me to start by adding memory to see what the result would be. I would think, though, at current PC costs, you would want to add a second PC that runs your IE, messenger, TV Tuner, etc. A machine that is dedicated for that.

    For example, I use Beyond TV for my Bloomberg and other TV displays. That software is a massive resource hog, which I would think your ATIMMC is as well. Once I turn that process off, it frees up at least 15% usually and a ton of RAM. Move your none-trading related processes to another machine and confine one machine to just trading.

    Have you considered this?
     
    #31     Dec 4, 2005
  2. The original question was will more memory help with a heavy processor load. The answer is above. If you are swapping/paging (because you do not have enough memory) then adding memory will definitely help; if not its questionable.

    I'm not sure I agree that adding more memory will help with an IO bound system because of increased buffers/cache. That really depends a lot on what kind of IO the apps are doing.

    In any case memory is so cheap that its worth adding a second gig of system ram to see if it helps. There are also "tweak" programs that you can use to tune the OS to take advantage of additional memory.
     
    #32     Dec 4, 2005
  3. Quote from winter:

    The original question was will more memory help with a heavy processor load.

    It's very easy to misdiagnose an IO problem as a CPU problem. From what I've seen in this thread it screams IO bound to me.

    I'm not sure I agree that adding more memory will help with an IO bound system because of increased buffers/cache. That really depends a lot on what kind of IO the apps are doing.

    There's precious few applications that won't find a great deal of cache locality in a few gigs of buffer cache.

    Here's an example. Benchmark numbers for a program analyzing a large (10G) PostgreSQL database. Mixed random reads and writes:

    1G memory, no RAID: 309m21.745s
    2G memory, no RAID: 47m53.257s
    2G memory, software RAID5: 49m1.084s
    2G memory, software RAID0: 46m33.280s

    In any case memory is so cheap that its worth adding a second gig of system ram to see if it helps.

    That's the best reason. :)

    Martin
     
    #33     Dec 4, 2005
  4. Agreed but I think its also helpful to answer the question as written so that others reading the thread will get a straight answer. That was my point in simply answering the original question without making guesses about the underlying problem.

    Databases are an excellent example of an application that will take advantage of extra memory thrown at them because they are written to utilize additional memory when available. Most applications are not constructed this way.

    So if the app wont use the extra memory the question becomes will the OS, given a wide excess of memory, take advantage of the surplus memory (in ways that will reduce cpu load or speed up applications?). And again I'm taking about memory beyond the minimums to prevent the need for paging and the basic OS requirements. In most cases the answer is no, excess memory provided to the OS quickly has diminishing benefits for overall system performance.
     
    #34     Dec 4, 2005
  5. ft71,

    i am already split betwen 2 ibm workstations each dual xeon proccessors...

    i have run out of physical space..i am fairly pared down but i intend to start seeing what i really can do without..

    drop items one at a time and see how it goes...

    remember this...
     
    #35     Dec 4, 2005
  6. coldrunner,

    i am running mirriored systems with 10k scsi drives...

    i know it's not faster just safer...

    but will look into I/O issues

    thanks
     
    #36     Dec 4, 2005
  7. Yes. Any modern OS uses uncommitted memory as a filesystem buffer cache. "Free" memory is very useful in making your system perform better, particularly if it is IO bound (which, unless you're trying to discover a new prime number, it probably is).

    The benchmarks I quoted used the default Postgres buffer cache of only 512k. Otherwise it was relying on the kernel buffer cache. That is the preferred configuration unless you have a dedicated database server.

    Martin
     
    #37     Dec 4, 2005
  8. many thanks to all that have offered help and ideas...

    turns out one of the drives in my raid became corrupted so it took a major chunk of resources to work around this...

    i also sprang for some more ram...

    so after reformatting and reinstalling my software thing are MUCH better...

    thanks again...

    went from 1 gig to 5 gig of ram and the hard drive barely spins....:D
     
    #38     Dec 7, 2005
  9. Are you using the Intel Application Accelerator Raid program that comes with winxp? I suspect that my HD is probably corrupted as well or getting there.


     
    #39     Dec 7, 2005
  10. no...

    i am using the built in raid 0 of the ibm workstation...

    lsi logic i belive...
     
    #40     Dec 7, 2005