So which one can use the faster memory?

TexTex Dallas/Ft. Worth
edited June 2005 in Hardware
OK I have two motherboards. Both are server motherboards with no overclocking.

One has a pair of opteron 246's. One has a pair of xeon Nocona's with 800fsb. The opteron mb is a msi k8d. The xeon is a supermicro.

I have 2gb (512mb x 4) of pc2700 ddr ecc reg. And 2gb (512mb x 4) of pc3200 ddr ecc reg.

So is their an advantage to which one would best use the pc3200 memory?

Tex

Comments

  • deicistdeicist Manchester, UK
    edited June 2005
    AFAIK Intels do better Asynch, so the intel would deal with the lower rated RAM better... although, having said that, while AMDs traditionally like to run 1:1 the A64 architecture seems to deal with Asynch memory better.... so in short, I got nothing. My gut says put the 3200 in the AMD and the 2700 in the intel though.
  • muddocktormuddocktor
    edited June 2005
    I would say to do just the opposite of what deicist says myself. The Xeon system uses a shared memory architecture and it needs all the bandwidth you can give it a lot more than the Opteron, IMO. I'm basing this on what I've seen posted by people folding BP work with Xeon systems, which really requires a lot of bandwidth.
  • mmonninmmonnin Centreville, VA
    edited June 2005
    Yeah try the Xeons, they are mem bandwidth starved in the first place no matter what memory you put in there since they each dont have their own memory controller.
  • FlintstoneFlintstone SE Florida
    edited June 2005
    Check the steppings of the Opterons as the older ones won't use the 3200 anyway and the problem will solve itself, no?
  • TexTex Dallas/Ft. Worth
    edited June 2005
    only true of the slower opterons. All the 246's will run pc3200.

    Tex
  • FlintstoneFlintstone SE Florida
    edited June 2005
    Not necessarily true. Check out all of the threads over at AMD forums regarding the populating of the memory slots and how the memory controller reacts to 2 gigs of dual rank modules. Unless it's a much later stepping (the one just prior to e and e), anything over 2 sticks of dual rank memory modules, per AMD specs, throttles the memory controller back to PC 2700 speeds no matter what speed the memory is. Tyan has just released a bios to allow a workaround for my board, but it is a design spec from AMD.
    But don't let any of that stop you from installing it in both and running memory benches to see which is faster!! I know you have nothing but time like me!!! ;D;D;D
  • TexTex Dallas/Ft. Worth
    edited June 2005
    All the stuff at 2cpu.com stated that the early 240 and 242's didnt work. (I owned a couple sets of those btw...) But all the 246's and above would work.

    Tex
  • FlintstoneFlintstone SE Florida
    edited June 2005
    It's a different issue.

    Give this a read:

    # Note: This BIOS follows AMD recommendations for DDR bus speed as a function of loading. As a result if you are running CG or older stepping CPU AND more than 6 loads DDR 400 memory the BIOS will automatically set the bus speed to DDR 333 speeds. For more information see the AMD BIOS and Kernel Developer's Guide (PID# 26094) - here

    Tyan's page where it came from is here:

    http://www.tyan.com/support/html/b_s2885.html
  • TexTex Dallas/Ft. Worth
    edited June 2005
    6 "loads" of ddr? If thats sticks.... then I'm ok as I am using four sticks and it only has 6 slots max.
  • FlintstoneFlintstone SE Florida
    edited June 2005
    No, if your using "dual rank" modules, 4 X 512 = 8 loads. At least that's how I understand it. This went on for a couple of months while Tyan made the decision to write a bios to ignore AMD's specs and came up with a disclaimer to use at your own risk.

    I believe each "rank" equals a "load" which seems to equal 1 side of a memory dimm. From my reading, a single sided dimm is a single rank dimm and would equal 1 load. A dual sided dimm is a dual rank dimm and would equal 2 loads.

    I know it's bullcrap, but it's something I had to deal with when I upgraded the amount of my memory and ran a bench and saw the speed drop. Had to revert to an older bios that ran the memory at a non-spec speed, actually defaulted to whatever the spd chip in the dimm told it to run it at, to get my performance back. I haven't upgraded to the latest bios that allows the user to select the memory speed yet as I have no other issues. But according to the AMD white paper, it is an across the board (excuse the pun) issue.
  • TheBaronTheBaron Austin, TX
    edited June 2005
    that is very odd, glad I didn't buy an opteron system and run into that problem, it'd piss me off
  • FlintstoneFlintstone SE Florida
    edited June 2005
    BUT, come to think of it, if you're only using 2 sticks per cpu and the memory banks are segregated as on the Tyan, 2 or 4 for each processor, then you've only got 4 loads per processor and should be fine. My problem came because I'm running 4 sticks per processor in dual channel mode with dual sided dimms and therefore had 8 loads per processor.

    Anyway, If nothing else, consider yourself enlightened!! ;D;D;D
  • DonutDonut Maine New
    edited June 2005
    I was wondering also, thanks for the enlightenment.
  • TexTex Dallas/Ft. Worth
    edited June 2005
    Flintstone: Great info and as always.....

    Love Ya Man.

    Sounds like two sticks per cpu should be a no-brainer.

    Tex

    PS the pc3200 got here today. I got VRD training all day through tomorrow but if I get time I'll test in the oipteron.
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