DDR400 DRAM speed drops to 333mhz with 4 strips!?

Discussion in 'PC hardware help' started by MaccerM, Nov 29, 2007.

  1. MaccerM

    MaccerM Regular member

    Joined:
    Aug 6, 2007
    Messages:
    141
    Likes Received:
    0
    Trophy Points:
    26
    I am a relative noob when it comes to Athlon 64 chips and their motherboards with their HTT etc as opposed to the good old FSB!
    My brother has a A64 3200+ in an Asus A8V-VM (cheapo) motherboard. I recently helped him change one of his ram stips (4x 512mb Corsair Value Select DDR400) as he had 3 double sided strips and one single and the DRAM wasn't running dual channel. Also, the bios post would say DRAM Speed 333mhz. I have got him a double sided strip so all 4 match and I have noticed something curious.
    When you have one pair installed (either pair) it boots up saying
    Dram 400mhz
    Dual channel mode 128bit

    However when you install the other pair the dram speed always drops down to 333mhz again.
    Anyone have any idea why? What can I do to get it up to the rated speed?
     
  2. cee43ja1

    cee43ja1 Active member

    Joined:
    Sep 14, 2007
    Messages:
    4,134
    Likes Received:
    1
    Trophy Points:
    68
    to guarantee dual channel, all four sticks should be the same brand and types. i think using different brands won't enable dual channel (can be wrong, someone correct me if i am)
     
  3. MaccerM

    MaccerM Regular member

    Joined:
    Aug 6, 2007
    Messages:
    141
    Likes Received:
    0
    Trophy Points:
    26
    They are all corsair VS512400's. All 16x32 mb double sided strips. Two of them are a matched pair (i.e the serial no.s are 1 different) Both pairs work individually in dual channel mode at 400 mhz, but when you use all four strips the bios post says they're in dual channel but at 333mhz!?
    As I've said, both the pairs will boot in dual channel mode at 400mhz when you just use a single pair - surely this would mean that there isn't a problem with the matching of the two that have different serials - otherwise those two wouldn't boot in dual channel when by themselves?
     
    Last edited: Nov 29, 2007
  4. cee43ja1

    cee43ja1 Active member

    Joined:
    Sep 14, 2007
    Messages:
    4,134
    Likes Received:
    1
    Trophy Points:
    68
    i think if you use two matched pair sets, then dual channel should run at 400. (still can be wrong)

    is there any settings in the bios where you can change the ram speed? if there is, change it from auto to ddr400; this will make it run at 400mhz no matter what.
     

Share This Page