SSD for OSX/apps AND scratch?

Discussion in 'Buying Tips and Advice' started by analog guy, Jan 2, 2014.

  1. analog guy macrumors 6502

    Mar 6, 2009
    long story short, i'm contemplating the proper PCIe SSD size on iMacs and nMPs.

    typically i would put my OS & apps on the internal SSD and everything else on other drives. since these new machines have SSDs which may never be replaceable but are also incredibly fast, i am wondering if i should buy more storage than i need with the thought that i should point my scratch drive to it as well (e.g., photoshop scratch).

    i do plan to bump up RAM a fair bit, which might reduce but not eliminate the need for scratch.

    my other alternative is scratch via SSD over thunderbolt.

    thanks for the thoughts!
  2. Bear macrumors G3

    Jul 23, 2002
    Sol III - Terra
    I'd recommend using the internal disk for the scratch space as well. Some applications do not make it easy to move their scratch space. Also, if you wind up needing more space for applications and such you could then move the scratch space to an external drive.
  3. ApfelKuchen macrumors 68030

    Aug 28, 2012
    Between the coasts
    We now know that the SSD on the nMP is user-upgradable, so your strategy for those might be different than for the laptops.

    These decisions have always been economically driven, and the question is as old as computing itself. The answer keeps changing, because the cost of fast storage keeps dropping. I recall making the bold decisions to configure a PC with a 20mb HDD plus floppy, rather than dual floppies, and a few years later, to install more than the DOS-maximum addressable RAM (was that 512k, or 640k?) and to buy extended memory management software to handle the remainder of (gasp!) the 1mb of installed RAM.

    For my money, your question (scratch disk on SSD or disk, inboard or outboard) should have been the one asked in these forums two or more years ago, but conventional wisdom is always behind the curve. To me, the notion that applications and OS require speed, but data does not benefit from fast storage is ridiculous, especially when you're talking about the large files we find in electronic media and databases.

    Using SSD solely for OS and apps is the equivalent, in a kitchen, of storing all the pots and pans near at hand, but placing the refrigerator in another room. Now, in a commercial kitchen (and in a professional media studio) bulk storage demands are so high, and the number of cooks accessing the materials so large, that long-term storage has to be distant from the kitchen's core. The trick then is to fetch all the ingredients needed for the dish in one trip, and to organize them right at the cooking station along with the necessary tools ("mise en place"). You need a stove (CPU), a pot big enough to hold the dish as you prepare it (RAM), and a surrounding work area large enough to hold all the remaining tools and ingredients (SSD by today's standards). The distant, walk-in refrigerator and pantries should be visited as seldom as possible.

    Should you add more RAM or a larger SSD? For the nMP 16GB of additional RAM currently costs $400, 256GB of additional SSD costs $300. SSD is 5-10 times faster than an HDD. The question for me isn't whether the scratch belongs on SSD, but simply whether that SSD should be outboard or inboard? Personally, I feel more comfy with it inboard, so I'd probably pay the "Apple Tax" (boy, do I hate that term, as if Apple was the only manufacturer who charges more for their memory components). I can't say an SSD on TB2 is necessarily going to cost most of us a whole lot in productivity compared to inboard. I leave that to Anand Lal Shimpi.
  4. Bear macrumors G3

    Jul 23, 2002
    Sol III - Terra
    Yes, but at what cost? That's the question and nobody knows the answer just yet.
  5. analog guy thread starter macrumors 6502

    Mar 6, 2009
    thanks, all.

    apfel: i understand your points. in my initial post i left out some info for the sake of brevity.

    today, i run a 256GB SSD for OS & apps (& a virtual machine) and SSDs for data as well.

    i've ordered an iMac with 512GB SSD and an nMP with 512 internal, in order to decide which machine will suit me better. i figured that 512 vs 256 was a nice bump, given that today i use about 180-200GB on my internal SSD.

    however, i've been debating whether to go 1TB and max it out.

    even if i were to go 1TB internal, it would not be enough to house the other data that i want to store. thus, i'll be running SSDs via TB or TB2.

    i'd always read that the scratch drive should be on a separate drive as 2 drives could, in theory, be accessed at the same time, but with the speed of PCIe SSD (or SSD over TB2?) perhaps they are so fast that this is a non-issue. i'd been thinking of putting the scratch drive on SSD over TB/TB2, too….IF i did it externally.

    i am sold on all data on SSDs.

    either iMac or nMP (whichever i keep) will offer a step up in RAM. i run 16 today in my MP3,1 and am very likely to move to 32GB.

  6. analog guy thread starter macrumors 6502

    Mar 6, 2009
    ps i've used a RAID10 for speed and mirroring (in addition to external backup) for my data for quite some time, so i don't make a distinction that OS/apps benefit from fast access while the rest of data does not.

    thank you for your reply; i do appreciate it.

    still wondering about whether to include scratch on that boot/apps SSD and get an even bigger one (1TB vs 512, when 512 is 2x my current boot/apps SSD size) or whether to put the scratch on an external SSD connected via TB/TB2.

    other data will be in a TB enclosure, on SSD. don't know if the scratch SSD is in this same enclosure if I might as well put it on the same drive as the data drives, as it is all the same bandwidth.
  7. Bear macrumors G3

    Jul 23, 2002
    Sol III - Terra
    I suggest trying the internal SSD for scratch it's going to be faster than any single external SSD will be. And I would start with it on the internal disk if I were you.

    And if you do decide to put the scratch area on an external disk, putting it on a separate disk even in the same enclosure will still be faster than putting it on the data disk unless the data disk is part of a raid set.
  8. linuxfanatik macrumors newbie

    Jan 2, 2014
    Northumberland, UK.
    If you can afford it, go for the largest SSD that's out there in the wild - that would be around one terabyte at the moment in England, though it may be of a higher TB in the US of A. I started with Unix (whilst working with Plessey PLC in Liverpool, England) - which was passed down via a fragment of code from Berkeley University (California) in the early 1970's. I've never looked back.:cool:

Share This Page