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Dealing with a useless BIOS

Discussion in 'Memory' started by wryun, Jul 15, 2010.

  1. wryun

    wryun Member

    Joined:
    Apr 19, 2006
    Messages:
    105
    I've just upgraded my CPU on my Asus T3-P5945GCX barebone, which has a very sparse BIOS. In particular, it has no ability to set any clock frequencies/RAM dividers (grr).

    So, after a few days of my shiny new (ok, used) E8500, I pulled up CPU-Z to discover that it's reporting my RAM as running at 250mhz (4:3 divider). Ok, that's odd, when it used to happily run at 333mhz when I had my old E2160.

    setfsb reports it as running at 333mhz; of course, setfsb also reveals the dodgy stuff Asus is doing to get it to get the FSB to 333mhz on this old 945gc (namely, overclocking the PCI-E frequency to 115mhz, which other boards using this chipset mention but Asus glosses over). However, I think setfsb might be misreporting this frequency, because I'm pretty sure it used to before with my old CPU... I think this is because it expects the CV122CPVG clockgen on my board to be on a different motherboard (ASUS P5LD2-VM SE).

    I think what is happening here is that there's no SPD info on one of the RAM modules for DDR2-667, only 400, 533 and 800 (I'm being a bad boy and running unmatched memory). And so the BIOS happily drops back to using the 4:3 divider since it has no proper info about 333mhz (but why did it work before? Or am I misremembering?). Does this sound reasonable? Does this mean I should be rewriting the SPD info? How risky is that? What's another good way to check this?

    Sorry for the long story :)
     
  2. oohms

    oohms Member

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    Try swapping the sticks around, and see if it'll read the SPD from the other one instead - sometimes this works with certain motherboards/mismatched ram combinations
     
  3. OP
    OP
    wryun

    wryun Member

    Joined:
    Apr 19, 2006
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    Just went and swapped the RAM with another computer to get some matched sticks, then used SPDTool to rewrite them as 333 rather than 400... apparently, completely useless. Still stuck on 250.

    Maybe I'm doing the rewriting wrong; but cpu-z is picking it up properly (just changed the one value).

    Also, the BIOS is reporting the RAM as PC2-3200 dual channel (???).
     
    Last edited: Jul 15, 2010
  4. oohms

    oohms Member

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    Could be because the 945GC chipset doesn't officially support 1333 fsb, only 533/800 - that would explain why the sticks worked with the E2160, as it uses 800 fsb

    It probably uses the 4:3 divider to keep it stable at 1333 >_>
     
    Last edited: Jul 15, 2010
  5. OP
    OP
    wryun

    wryun Member

    Joined:
    Apr 19, 2006
    Messages:
    105
    Yeah, possibly, though I think the Intel specs site is wrong (seems to be officially ok with 1066 based on this model and other 945GC-A2 ones).

    But looking at the ASRock manual for a similar overclocked 945gc-a2 motherboard, they mention the RAM running at 250mhz only if it's DDR2-533, presumably because there isn't an appropriate divider setting. Maybe I'll try to hassle Asus support.
     

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