One week with Single Quad Core MacPro (long)

Discussion in 'Mac Pro' started by Derek87, Feb 20, 2009.

  1. Derek87 macrumors 6502

    Jan 29, 2009

    - i've been a mac user for two decades with a lot of unix/linux stuff thrown in between.
    - other recent machines have included:
    1. first gen 2 x Dual core Xeon 3ghz Mac Pro with 8gb RAM at work
    2. 2nd gen Macbook 2.0ghz with 2 gb RAM (work owned as well)
    3. a recently dead (and this replaced it) dual G5 1.8ghz with 3 gb RAM

    if #3 hadn't died, i had planned on keeping it at least 1.5-2 more years as it was serving my needs well. but sometimes your hand is forced...about a month ago, the dual G5 died...all diagnostics and work suggest a logic board failure which wasn't worth fixing. i contemplated a number options including buying something used, trying to wait until June or whenever the new MacPro would arrive, and strongly considered buying the new white macbook (with nvidia graphics) for a kludged "mac mini" which had easily upgradeable RAM and hard drive.

    but in the end, a discount from a friend who works at apple and my need for a machine now + the attractiveness of expandabibility for RAM and HD space thrust me in the MacPro direction.

    finally, i'm not a power user...i am at work in certain ways -- i do computational fluid dynamics which eats up horsepower (my big stuff goes to "supercomputers")...and so does analysis of large data sets in matlab. but for home, i do web browsing, word processing, spreadsheets, photoshop, and converting videos (my mac serves as my "poor man's Tivo" using a Miglia HD tuner i bought years ago).

    After a week with the machine...

    i can provide the following feedback...

    (i) even though i don't think i need a lot...i installed 6 gb to start and that makes a big difference. i had it with the basic 2gb for a few days and i could really feel the machine was being held back. i bought 2x2gb from Memory America and the extra 4gb really improves performance a lot!
    (ii) RAM runs very cool...using istat, i see it typically in the 120 oF range which is 20 oF less than on my MacPro at work...also, interesting enough, the Memory America Ram typically runs 5-10 oF cooler than the stock Apple chips.
    (iii) is 6 gb enough? i'm beginning to wonder. i've topped off at about 5.2 gb active although usually, it's in the 3-4 gb range with the rest allocated as "cache." i can only guess Photoshop is gobbling up whatever it sees even if i'm not doing anything complicated...RAM is cheap, so i'm going to see how things go for the next few weeks...and if needed, i'll bump it to 10gb... but i'm surprised to see how much has been used in my first full week of ownership. i thought i'd never touch 6gb at home, but that may not be the case...

    i never believed it, but now i am a believer. disk performance is a lot better if you have a empty system/boot disk. with only 200 gb of the 500 gb being used, the performance really is fast compared to my nearly full main drive at work. i need to perhaps rethink my work strategy to correct for this shortcoming on my older MacPro

    for me, 4 cores on the single chip are MORE than enough. the machine barely breaks a sweat. i think the only thing i do that uses more than 2 cores is that's a nice use, but i'm now glad i saved the extra few hundred in not going with 8 cores and saving the money for RAM and hard drive purchases.

    very impressed in how easy RAM and HD installation has become. not that the dual G5 was that hard, but this is so clean and easy these days. i also like the possibility of installing up to 6 hard drives with the single optical if i ever see that need down the road.

    - How much RAM is enough? i know there are varying perspectives here, but i am surprised by what i've been seeing in my early ownership. i never thought that 3gb was holding me back with my old dual G5, but now i'm wondering. [anecdotally, even though my macbook had more "horsepower," i had been finding that it lagged in performance compared to my dual G5...that may have been a RAM and video bottleneck]

    - i plant to salvage the old superdrive from my dual G5 and put it into the 2nd optical bay: with multiple cores, can one important two CDs at once in itunes?

    - is it wise to have one's entire home directory on a 2nd disk or just the large files [music/videos/pictures]? i can see some downsides of having the whole "home" on a second disk, but i guess when a HD dies (either boot or user disk), it's going to suck regardless. (backup notwithstanding)

    in short, i'm glad i didn't wait any longer. not having a main computer at home (i was relegated to using my work-owned laptop and ipod touch for the past month) wasn't much fun. i'm sure something faster and better is coming down the pipe, but sometimes, you just have to make the purchase and avoid (hopefully) looking over your shoulder... :rolleyes:

    thanks for all the great info on this forum!
  2. Macpropro80 macrumors 6502

    Jan 31, 2009
    "computational fluid dynamics"

    Can you explain to me what that is in lame-mans terms. Im just curious.
  3. Derek87 thread starter macrumors 6502

    Jan 29, 2009
    sure, i'll try: CFD, for me in particular, involves trying to model how fluid (water, but it could be air) moves in the environment by solving Newton's second law (F=ma, from your days of physics)

    unfortunately, the detailed expression of that seemingly innocuous "F=ma" is a system of four nonlinear, coupled, partial differential equations. (sometimes called the Naviar-Stokes Equations--check out wikipedia for a quick look)

    these are very difficult to solve, and for any real fluid system in the environment require a lot of RAM and computational power, even with some of the simplifying assumptions my colleagues and i often have to make (ie, solving for real spatial scales and at fine enough time resolution).

    hope that helps.

    ps. even without doing "CFD" the other part of my computer usage as a scientist involves analyzing large datasets. these can often be in the gigabytes range. to load such data sets into matlab requires a lot of RAM. unfortunately, Mathworks hasn't yet released a 64 bit version of matlab, so those computers are capped at ~2gb. but i look forward to the day when i can max out my machine with 32 gb of RAM and load in the large datasets in their entire for analysis. (right now, i break it into pieces and/or do some "preprocessing/analysis" in Fortran since it's a bit more memory efficient...
  4. Outsider macrumors regular


    Mar 25, 2002
    North Carolina
    Very cool work you do there. Thanks for sharing and expanding on it.

    1. Depending on your applications, how many you'll need open at a time, and how much they can access, you can budget how much RAM will suit you. Photoshop, for example, can't utilize more than 3GB on your system so if you were using that and some other apps like Illustrator, 4GB-5GB would be sufficient. In any case, 4GB seems like the lower end of what you should have, while 8GB would be optimal. Open up Activity monitor and check your RAM usage through out the day to help determine if you need more than the 6GB you have now.

    2. No, itunes doesn't have this capability.

    3. If you have a lot of user files that depend on a database like iPhoto or iTunes, then you should have it on a drive that is permanently attached to your computer (internally). Either your boot drive our a secondary SATA drive. Performance will be the same more or less. You should be backing both drives up to a 3rd drive in case of a disaster.

    Enjoy your new rig!
  5. akdj macrumors 65816


    Mar 10, 2008
    After Effects/FCP are my tools, maybe PS 20% of the time and I think you're need is greater than mine for RAM:) Mathematically, when Snow Leopard's use of multiple cores and your (proprietary) software upgrades to 64bit, you will be able to use every bit of you Mac's max:) (32g). Right now, if you're bumping into a 90%max (5.4G/6 available), I would pop another 2 gigs in for head room. (Especially staying within the law of diminishing returns, dollars per GB) and ensuring ALL slots have a stick. Especially if you're able to tax the system even more. Until we get true 64bit performance, the RAM is our Interstate to speed.

    Sounds like really cool work you're doing. Just getting to see a super computer in use would be a hoot for me.

    Take care

  6. Horst Guest

    Jan 10, 2006
    Some pointers here .

    More Ram is good for you, no matter what they say ;) .
    8 - 12GB are really affordable for the MP, and should work well for most uses and moderate multi-tasking .

    For some applications, like Photoshop, dedicated drives for data and scratch can make a huge difference ; but that really depends on your needs.

    If you work with big files a lot, fragmentation comes into play as well, especially if you tend to fill up your harddrives to the brim.
    It is recommended that you keep about 20% of your system drive empty at all times, and reformat scratch and temporary data drives frequently.
  7. Derek87 thread starter macrumors 6502

    Jan 29, 2009
    at home (on my single quad), i don't think i am using the resources you are for FCP/AE. i am going to see how things go with the 6gb for now. it's not expensive to go to 10gb, then again, if i'm not using it, it's money better spent or saved for something else.

    even at work, my 8GB older 2xdual core Xeon is enough for almost everything.

    re: supercomputer ... interestingly enough, most "supercomputers" these days are a cluster of many (1024 or more) linux quad core xeon workstations (there are some mac based ones, too, i believe.) all tied together. it should be noted that it takes very careful coding and thought process to reap the benefits of such parallel computing. (that's not my cup of tea: but colleagues do that well and i end up using their code. :) )

    on a different note, i was amazed at how fast Handbrake runs with 4 cores on the Intel architecture compared to what i was getting out of my old dual G5. i mean, we're talking about many folds increase...can't recall the old rate, but i am guessing i'm experiencing a 5-10x speedup!

  8. wisty macrumors regular

    Feb 18, 2009
    CFD is used in turbine design (jets, planes, and wind generators), simulating ocean behavior, car aerodynamics, forging (manufacturing), special effects in movies, simulating nuclear reactors, weather predictions and all sorts of other stuff. It's what most of the top 500 supercomputers do, I think.
  9. justit macrumors 6502a

    Dec 1, 2007
    I've got the same machine but with 10GB. It does run hotter with more RAM, and yes that Apple 2 Gigs is much hotter than my other crucual ram.

    I'm tempted to yank out the Apple Ram and live with 8 Gig :p
  10. Rt&Dzine macrumors 6502a


    Oct 8, 2008
    You may find this RAM chart interesting. Placement of RAM in the single processor Mac Pro isn't as performance sensitive as in the 2-processor.

    I have the single quad core and currently am using 8GB of RAM. At different times I've had 2, 6, and 10. To tell you the truth, I haven't noticed that much difference between 6, 8 and 10, except that some of the RAM was much hotter when I had the 10GB. But one stick went bad so that may have been the problem. Currently they all run about 113 f to 121 f. Photoshop runs slightly better with the 8 versus 6.
  11. sj04 macrumors newbie

    Feb 22, 2009
    Hi, I am considering to buy a new Mac Pro. I need it to do some Monte Carlo simulations and a lot of statistical math works. I use Matlab too. Matlab has a option to switch on/off 'Enable multithreaded computation'. My question is even if you enable this optional, is Matlab still using 1 or 2 cores? Thanks.
  12. Derek87 thread starter macrumors 6502

    Jan 29, 2009
    i haven't played with this option too much in matlab. i leave it on and from what i can tell, it CAN use 4 cores (my work machine with matlab is 2 x dual core Xeons).

    interestingly enough, i found that if you type "bench" you can see that some benchmarks are slower as you get to use more than 2 cores! shows that the code many not necessarily benefit from more cores.

    for my uses, i want a 64 bit version (there actually is a beta out there and i have been way to busy to download and test/try it out) is more relevant so i could use more RAM.

    now thinking about it, i probably should set it to 2 cores (you can specify how many you let Matlab use) and be done with it at work.

    if you get an 8 core machine, you may want to play around to see if performance improves or plateau's or worsens with more cores allocated.
  13. polaris20 macrumors 68020

    Jul 13, 2008
    To the OP, I'm very interested to hear what you're using for CFD apps, as I work at an engineering firm, and we currently run Fluent, Gambit, and StarCCM+ on Linux, but I much prefer OS X to Linux, especially for administration.
  14. Derek87 thread starter macrumors 6502

    Jan 29, 2009
    unfortunately, no experience running any of the three you list on OS X. there are people in my group that use the former two with Linux. i don't see why they couldn't/shouldn't be compiled to run under OS X, but don't have any advice/experience to help. :\

  15. rylin macrumors 6502

    Aug 18, 2006
    Great thread!
    Personally I'm considering a MP vs. a new iMac at home.
    I "need" a minimum of 4 cores, "want" 8.

    To me (photo editing, movie editing, a fair bit of virtualization -- i.e. 8-16 VMs ideal), CPU is somewhat important, but is a distant second to memory and disk speed.

    I can easily build a storage solution giving me a few hundred MB/sec.
    If pushed, I guess I could make that a gigabyte or three, meaning storage as fast as memory from just a few years ago :p

    It's nice to see that people are actually enjoying their 1xquad MPs on here :)
    It could quite possibly be a good alternative for me, even though I'd prefer it if I could get some real toys at work instead ;)

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