RAMdisk and fraps

Discussion in 'Computer Hardware and Software, General Discussion' started by plonk420, Nov 10, 2011.

  1. and now for something completely different: Dataram Ramdisk ($15) http://memory.dataram.com/products-and-services/software/ramdisk
    if you have a retarded amount of spare RAM, and only want/need a small file, you can try this. the demo lets you create a 4GB partition for free, even up to Win7 and Server 2008 R2.
    Random 4K Read: 542MB/s (sequential: 4096)
    Random 4K Write: 414MB/s (sequential: 5472)
    (some standard DDR3-1333, G.Skill either Sniper or Ripjaws)

    note, those numbers will drop if other apps are using RAM. e.g. i was running distributed computing on all cores, and my 4K Read was 300-some odd MB/sec before i stopped the test.


    i'm considering buying it if i can figure out what system i'm going to put it on. seems like you need to email them for a new key if you uninstall from one system and install on another...or reinstall Windows.

    edit: (i think the CrystalDiskMark is app-bottlenecked. it maxes out a core)

    idle system stats:
    Random Read 4KB (QD=1) : 542.751 MB/s [132507.5 IOPS]
    Random Write 4KB (QD=1) : 414.825 MB/s [101275.6 IOPS]

    loaded system (x264 + wcg distributed computing on all cores) stats:
    Random Read 4KB (QD=1) : 363.810 MB/s [ 88820.8 IOPS]
    Random Write 4KB (QD=1) : 285.608 MB/s [ 69728.6 IOPS]

    edit2: proof of concept: http://forgottenwebsites.com/lulz/stargazer1080p60-crf22-subme11-muxed.mkv (note: low cpu consumption; see demoscene demo "Stargazer")
    raffriff likes this.
  2. raffriff

    raffriff Moderator Staff Member Site Contributor

  3. bos


    I've been experimenting with this and unfortunately this doesn't work too well because Fraps keeps all the files locked, so no off-loading can be done while recording.

    Creating a script that moves the files isn't difficult, see below batch file. It just loops every 10 seconds and attempts to move avi files somewhere else. If the file is in use, or "locked", then the move operation doesn't work. As soon as the file is NOT in use, or "unlocked", then the move operation works.

    move "[source path]\*.avi" "[dest path]"
    timeout.exe 10
    GOTO :start
    HOWEVER, as I mentioned above, Fraps keeps all files locked until you toggle off the recording button. This is a major flaw. In the other thread, heldiX was forced to toggle the recording button to keep a lower file size because of limited ram disk space. In actuality, you'd be forced to toggle anyway just to get Fraps to unlock the files. Toggling the recording button loses frames, as heldiX wrote:
    At the moment, Fraps can't be used unless you're ok with losing frames between toggling of the recording button. For me, this is unacceptable. There may be other capture software out there that has different file locking behavior.
    raffriff likes this.
  4. raffriff

    raffriff Moderator Staff Member Site Contributor

    Good work bos. That's terrible news though.
  5. bos


  6. raffriff

    raffriff Moderator Staff Member Site Contributor

    Interesting! ...here's what I gather from their test results:

    On this page, they compare CrystalDiskMark scores using a typical 7200 RPM HDD.
    There's only one test setup with deferred write enabled:
    Test (3) Level-I Cache: RAM 256MB, Level-II Cache: Invisible Memory 700MB, Defer Write: 3000s
    (100MB test length)
    No cache: Seq Write = 118 MB/s
    With cache: Seq Write = 8,866 MB/s
    Nice! ...but the Test Length is less than the cache size, so that's equivalent to writing straight to RAMdisk!

    OK, let's see this page, 2nd chart - writing to an SSD: Test length is 40GB; cache size is 1GB.
    When Transfer size = 512KB *, and Outstanding IO = 1;
    Without cache, IOPS = 479;
    With cache, IOPS = 506.
    479 IOPS = 479 writes/s x 512 KB/write = 245,248 KB/s or 239 MB/s
    506 IOPS = 506 writes/s x 512 KB/write = 259,072 KB/s or 253 MB/s
    So you get a 6% performance boost. Would there be more improvement with a HDD, or less? I don't know.

    So we have two extreme data points. Maybe it works this way: if your RAM cache is 4GB, you can capture an extra 4GB per "recording" before you have to stop and let the cache flush to disk; so...
    • If you need to capture 8GB, your performance is about 200% (4GB to RAM, 4GB to disk)
    • If you need to capture 12GB, your performance is about 150% (4GB to RAM, 8GB to disk)
    • etc...
    The performance boost should taper off as the recording gets longer. Theoretically.

    Another benefit might be smoothing-out of any freezes. Freezes seem to be caused by the time sometimes required for Windows to allocate new 4GB files. With a deferred write buffer the freezes might not be noticeable - you can "ride over them."

    * About the 512 KB transfer size: I got this by logging Fraps activity with Sysinternals Process Monitor. It's a great tool for seeing what Fraps, and the rest of the system, is doing.
  7. raffriff

    raffriff Moderator Staff Member Site Contributor

  8. ETAdmin

    ETAdmin Administrator Staff Member

    I've considered doing that, the problem is the space required can be incredibly prohibitive unless you have the cash to spend on the higher capacity SSD devices. Even with my Intel 160GB, I find myself running low on precious gigabytes after windows is installed and some basic apps/games are added into the mix. Adding fraps footage to it isn't possible at the moment.

    In my opinion the sweet spot for recorders with a decent budget will be the 512+ gb SSD's at a $200 price point. Lossless footage will be easily handled.

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