Enable BIOS Memory Remap Option with XP 32 bit?

Discussion in 'Memory' started by DEX1, Sep 11, 2008.

  1. DEX1

    DEX1 Limp Gawd

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    :confused:Enable BIOS Memory Remap Option with XP 32 bit?

    I am in the process of upgrading my signature PC. So far I’ve swapped an Asus P5B Deluxe & E6300 for an Asus P5Q Pro & E8500. Next I am going to replace the 2GB (2x1) RAM with 4GB (2x2) on the way to eventually getting VISTA 64 bit.

    Meanwhile I’ve read conflicting info on the “memory Remap” BIOS option. The Asus manual e.g. says to Disable with a 32 bit OS leaving only 3GB accessible to the OS. I’ve read elsewhere that it’s OK to Enable this option with 4GB RAM and XP 32 to get access to all 4GB although XP 32 will show use of less than 4GB.

    I would appreciate advice from anyone who has used 4GB of RAM with XP 32.
     
  2. Mike Clements

    Mike Clements Gone but not Forgotten

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    On my P5K Deluxe with 4GB of memory, I did not have to mess with this setting at all. Using a 512mb video card, I have 3.25GB usable. It should be teh same on a P45 MOBO.
     
  3. Big Lar

    Big Lar Limp Gawd

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    I have the P5Q-D here and its enabled in bios, I have a 768mb vid card and it shows I have 3.25 GB of ram in Windows XP 32 bit with 4gb of ram. In other words, I did not need to disable it.

    Larry
     
  4. Surly73

    Surly73 [H]ard|Gawd

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    I have a P5B-E and 4x1GB.

    With it enabled, XP x86 sees 2GB. With it disabled XP x86 sees 3.x GB.
    With it enabled, Vista x64 sees 4GB. With it disabled Vista x64 sees 3.x GB.

    If you dual boot, you'll have to flip this option every time if you need max memory in both OSs.

    I had 2GB and only XP until recently, I just live with the same 2G in XP and 4G in Vista so I don't need to flip BIOS options.
     
  5. DEX1

    DEX1 Limp Gawd

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    Thanks I lot for the advice. I was surprised that the P5Q came with this field enabled by default with Asus assuming the average user would install a 64 bit OS. I guess the 64 bit tipping point has been breached.
     
  6. dnottis

    dnottis [H]ardness Supreme

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    Something is wrong with your system then.

    I have an Asus P5K-E, if you have 4GB or more you want it enabled. 32 bit OS will show ram - GPU ram. So if you have 4GB ram and 768MB 8800GTX XP will show 3.25GB free. If you have 4GB ram and 9800GX2 with 1GB it will show 3 GB free. Etc.

    In Vista x64 it will use all of your system ram and not be limited by the memory on the GPU.

    You definitely want to leave remap enabled if you have 4GB of ram though.
     
  7. pallesen

    pallesen Limp Gawd

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    As the asus documentation says, when using 32bit xp/vista, you want to disable memory remapping. They have implemented the function so it remaps after either 2 or 3GB (GB-aligned). That means you can lose additional 0-1GB of ram by having it enabled.
     
  8. Surly73

    Surly73 [H]ard|Gawd

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    Correct. As my post indicates, 32-bit OSs see the most RAM with remap DISABLED. Remap essentially puts any RAM above 2GB mapped in above the 4GB barrier so 32-bit OSs see NONE of the RAM >2GB with it enabled. With it disabled at least you get 4GB-(MMIO RAM).
     
  9. Big Lar

    Big Lar Limp Gawd

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    Well, it sure seems you are correct. I disabled Remap and my Everest bandwith increased and latency dropped, even shows whats available correctly now. I'll be dipped. TY for posting that, here I thought I had the setting correct, in which I did not.

    Larry
     
  10. trent

    trent n00b

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    I have Vista 32bit with 4x1GB. I've always left remapping at its default (enabled), because Vista reports 3,3xxMB accessible. When I read this thread, and particularly Big Lar's post, I went ahead and benchmarked my RAM with it enabled, rebooted and disabled remapping and benchmarked again. Interestingly I also got higher bandwidth and less latency. Nothing drastic but still there. Does that make sense? Why?
    BTW I have an 8800GS with 384MB, if that matters. I'm not quite understanding why the amount of graphic memory affects how much system memory is accessible ... but then again I am half asleep at the moment :p Oh ya and my mobo is a P5E-VM HDMI.

    1st benchmark is with remapping enabled, 2nd disabled.
    [​IMG] [​IMG]
     
  11. pallesen

    pallesen Limp Gawd

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    When enabled, it has to check if an address falls within the remapped area. That might be related.