Registered ECC Dimms

I'm thinking of building a new dual PIII 1000 system with a Supermicro SUPER 370DL3 motherboard <A HREF="http://www.supermicro.com/PRODUCT/MotherBoards/RCC_LE/370DL3.htm" target="_new">http://www.supermicro.com/PRODUCT/MotherBoards/RCC_LE/370DL3.htm</A>

I've been happy with Supermicro boards in the past. However, the ServerWorks III LE based motherboard requires "only registered ECC memory" and since I want 512 megs for graphics, this will add a considerable cost.

What exactly is gained by registered memory? (Or for that matter, what is registered memory and why is it called for?)

Will I gain stability by using registered ECC memory?

They recommend Wintec, ATP, Apacer, Dataram, Ventura Tech, Crucial Tech, Kingston, Kentron, or Corsair memory. I've never heard of many of these. Which is the best brand here?

Thanks.
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  1. Best brand in the above mentioned list is Corsair (www.corsairmicro.com).
    Registered memory differs from unbuffered memory in that with registered memory, the chipset doesn't electrically drive each and every RAM chip on each DIMM (as it has to with unbuffered memory), but only the register chips, 2 or 3 chips per DIMM. This prevents the poor north bridge chip from frying when trying to simultaneously drive 144 RAM chips.
    The rule of thumb is, that a "nermal" chipset can't drive more than 64 RAM chips. Desktop systems usually only have like 2 dimms of 16 chips each, but servers have much more memory (with ECC): 36 chips per DIMM is no exception. That's why real servers usually have registered modules; since servers also need ECC you see ALL registered modules in ECC; also you only see them in higher densities (256 MB and above) which makes them more expensive (besides the register & the ECC).
    ServerWorks chipsets are very sensitive, and they REQUIRE registered DIMMs. Apparently they can't drive more than a couple of RAM chips, i.e. register chips.
    Corsair has registered ECC modules that are certified for use with serverworks chipsets; they even have 128 MB registered ECC modules (that's quite small, previously they didn't have registered modules under 256 MB).

    "I'm a stream of noughts and crosses in your R.A.M."
  2. Thanks - I appreciate all the info.

    Corsair will run $328 for a 256MB DIMM = $656 total
    Kingston ValueRam appears to have an approved Registered ECC 256MB DIMM for $242 = $484 total

    I wonder if the Corsair is ~$175 better than the Kingston?

    I suppose RAM is probably not the place to be cheap. I do wish that there were some Registered ECC Cas2 DIMMS on SM's approved list (vs. Cas3)
  3. I agree that the Kingston sound much more attractive. I wouldn't go for it if the MOBO manufacturer hasn't approved of it though. And even if a manufacturer like SM claim memory is approved, I still don't think that really counts. Some manufacturers don't do anything more than plug a module in a board and see if it boots. That's one of the reasons why it took so long to discover the i820 MTH problem.
    From Corsair, I know they test modules with variable power supplies in temperature chambers ("ovens") for several days. Now that's rigid testing. And that can be seen in the price :(
    Registered PC133 memory usually is applied in servers/workstations with the Serverworks Server Set III chipset (LE, WS or HE variant). I know this chipset is VERY picky. Boards like the Tyan S1867 Thunder 2500 do not like non-approved RAM. Kingston memory is not on Tyan's recommendation list. From the top of my head: Memory Man, Corsair and Wiechmann Worx.
    Furthermore, I know Corsair are working on CAS2 registered modules, The first one out is the CM764S256-BX2; 100 MHz though.... I expect 133 MHz will come quite soon (or try www.corsairmicro.com and post a question in the Ask the Ram Guy forum).


    "I'm a stream of noughts and crosses in your R.A.M."
  4. I can recommend crucial's memory, I've never had problems with their ECC stuff, 64mb to 512mb DIMMS. However you mentionned you wanted 512 megs for graphics, you will have major problems since the Serverworks chipset does NOT support AGP, you are better off with a dual cpu wprokstation board
  5. Ouch - I didn't even notice that the Serverworks boards didn't have AGP, but you're right. Strange how I don't see things I don't want to.

    Unfortunately other than Serverworks (which, you're right, is out because of no AGP), my choices are
    1.) To go with Rambus, which everyone says is a huge waste of money.
    2.) To go with a Via chipset, which I just don't trust because I want my next computer to run for a week without crashing
    3.) To go with a really old BX/GX slot board which is rated up to 933 or 1000.
  6. OK, the Serverworks LE chipset does not support AGP.

    However, the Serverworks ServerSet III HE-SL Chipset does have a 2x AGP slot (from both Supermicro and Tyan).

    Unfortunately, these boards go for $800!

    So Intel may yet drive me to RIMMs :(
  7. I am stuck with the same problem, I work for a computer manufacturer and we have decided to suspend our workstation shipments while we wait for a suitable solution. Your last solution would be an 840 with a custom MTH (like AMI does), but I still don't recommend it, it's expensive and performance is not stellar due to the MTH (at least it works) If you plan on using the system as a PC (rather than a high-end business workstation), the VIA solution should be stable.
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