Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 33

Thread: Is ECC RAM worth it for a desktop PC?

  1. #21
    Join Date
    Apr 2013
    Posts
    103

    Default

    Quote Originally Posted by chithanh View Post
    About error rates:
    In the Google study they found that as memory chips aged, the number of errors would rise. This somewhat offset the higher number of errors due to higher capacity, as newer modules would typically have higher capacity.
    I remember that one, it was a good read. It's important to distinguish between error rate, and number of errors. Two very different things. Even if error rate stays the same, you will have double the number of errors, if you double the RAM capacity. The combination of a higher capacity plus a higher rate, equals a whole lot more errors. High capacity + age = double whammy.

    Quote Originally Posted by chithanh View Post
    On data corruption:
    RAID does not typically detect bit flip errors on hard disks, unless it employs some kind of data integrity check. Some expensive hardware RAID controllers do that, and ZFS RAID-Z does it too.
    All but the cheapest consumer-grade RAID controllers do integrity checking. Even the Linux kernel software RAID runs regular consistency checks. If the kernel software raid cannot read a block from one disk, it will remap that block to a new location, and reconstruct it from the other RAID members. You can also force a manual consistency check at any time, with "echo check >> /sys/block/md0/sync_action" assuming md0 is your array.

    You're correct though in that it doesn't detect disk errors on the fly (unless its accompanied by a read error), only during the regularly scheduled consistency check.

  2. #22
    Join Date
    Oct 2011
    Location
    Germany
    Posts
    239

    Default

    If you do many things in parallel and/or develop or/and build software 8GB Ram is not enough,
    Even when I do so a simple thing like building firefox (with arch its quite easy) it takes so much ram that ld gets killied which linking, if I doesn't watch what I have opened.

  3. #23
    Join Date
    Jul 2008
    Location
    Berlin, Germany
    Posts
    831

    Default

    Quote Originally Posted by torsionbar28 View Post
    You're correct though in that it doesn't detect disk errors on the fly (unless its accompanied by a read error), only during the regularly scheduled consistency check.
    Indeed, that helps you only if the disk reports an error. If the disk (or the controller, very nasty but happens) returns bogus data pretending everything is a-ok then you are still out of luck. And even during consistency check RAID can only detect, not correct the errors.

  4. #24
    Join Date
    Nov 2007
    Posts
    1,353

    Default

    Quote Originally Posted by DeiF View Post
    I'm planning a big upgrade for a desktop PC which is 6 years old already.
    The thing I've found it was more limited was in RAM quantity (only 2GB).
    My most memory demanding tasks now require about 8GB of RAM (without the OS, programs, etc).
    Since I want to be future-proof, I've decided to max out whatever is the maximum RAM in the new system (32GB)
    I'm currently considering to buy an Asus Crosshair V Formula Z, and an AMD FX-8350 CPU.
    Since both components support ECC RAM, and my budget seems to be enough to buy it, I'm considering that option.

    But, is it really worth it?
    How common are bit-flip errors in modern RAM?
    Is the performance drop noticeable?


    ECC RAM availability in my zone is pretty rare, but I've found this kit that may work:
    KVR16E11K4/32 (4x8GB DDR3 ECC 1600Mhz CAS 11)

    It isn't listed in the motherboard docs thought, so it's a bit risky. I haven't contacted Asus yet.
    My opinion is that ECC isnt really needed for desktop usage, but all RAM should be buffered, unfortunately the CPU makers don't agree with me....

  5. #25
    Join Date
    Sep 2012
    Posts
    732

    Default

    Quote Originally Posted by torsionbar28 View Post
    All but the cheapest consumer-grade RAID controllers do integrity checking. Even the Linux kernel software RAID runs regular consistency checks. If the kernel software raid cannot read a block from one disk, it will remap that block to a new location, and reconstruct it from the other RAID members. You can also force a manual consistency check at any time, with "echo check >> /sys/block/md0/sync_action" assuming md0 is your array.

    You're correct though in that it doesn't detect disk errors on the fly (unless its accompanied by a read error), only during the regularly scheduled consistency check.
    Indeed, that doesn't protect you against bitflips, which are not read/write errors but incorrect read/writes.
    Chechsumming helps against that, e.g. btrfs uses checksums in metadata, so it can recover from bitflip in RAID configuration.

  6. #26
    Join Date
    Jul 2008
    Location
    Greece
    Posts
    3,798

    Default

    It turns out that non-ECC RAM is actually a security risk, as bit flips can be exploited. "Bit-squatting" from Black Hat 2011:

    http://www.youtube.com/watch?v=_si0FYl_IOA

  7. #27
    Join Date
    Aug 2013
    Location
    Druten
    Posts
    1

    Default

    Is your desktop computer that mission critical?
    ECC is mainly used for high available mission critical systems.

  8. #28
    Join Date
    Aug 2011
    Location
    Hillsboro, Oregon
    Posts
    136

    Default

    If your motherboard supports ECC, absolutely go for it. I used to use it on my desktop, and it was rock solid...never had a single problem with it. It's a simple thing that makes your computer more robust and less likely to go haywire.

    These days, I don't use ECC just because most systems don't seem to have support for it. If they did, I'd switch back in a heartbeat.

  9. #29
    Join Date
    Jun 2008
    Posts
    6

    Default

    I seriously question the value of ECC memory. This is not because I believe bit-errors (and more importantly their detection) are unimportant but rather because there are simply so many other sources of error on a modern system.

    Properly evaluating the utility or necessity of ECC DRAM requires one to adopt a systems approach. First, can you list all sources of DRAM in your system? Every from the main memory to DRAM chips on hard disks and ethernet controllers. Secondly, of those chips how many of them are either ECC or utilise some kind of software pairty checking? Chances are at this point you'll find that your GPU (unless it is a workstation class card) has non-ECC memory.

    Next, can you tell me the error rates for all disks in your system? What about network connections? Checksums are not as strong as many like to make out. When SCP'ing large quantities of data over a local network it is not usual (often because of a bad cable) for errors to occur. These errors -- in my experience -- are usually picked up at the application level by SCP having first passed the Ethernet, IP and TCP checksums.

    If you're happy with all of that then it is time to move onto internal interconnects. Take moving data across the PCI(-e) bus as an example. Or between a S-ATA drive and the host controller. What is the error rate here?

    Finally, lets look at the CPU. What is the error rate (as in miscomputation of a result) here? Sure, it shouldn't happen, but still, for a meaningful evaluation of ECC memory to be made a rate is necessary.

    If this is still not enough lets go for the elephant in the room. Hardware and software bugs. I suspect these are orders of magnitude more prevalent than any of the hardware issues outlined above.

    Regards, Freddie.

  10. #30
    Join Date
    Sep 2012
    Posts
    358

    Default

    I would buy PC with ECC RAM, but cheapest CPU (Xeon 1225v3) costs about 210 Euro and cheapest motherboard (Asus P9D WS) costs 200 Euro.
    That CPU become outdated after about 3 years when integrated GPU become outdated because of driver support.
    Intel doesn't sell discrete GPUs. Open source drivers for AMD discrete GPUs aren't usable and there is too limited offer of fanless 28nm discrete GPUs.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •