Windows 7 32 bit on MSI MSI X99S SLI PLUS only 924 MB Ram available! (i expected around 3GB)?

[ruthan]

Hello,
at the start i just wanted to try install XP on X99 MB for retro gaming on multiboot system, but i ended with 920 MB of available RAM and i was unable to fix it, but i expected that is some XP 32 missing driver bug, but i now i have installed Win 7 32 bit supported OS and its the same, i have installed 2x8 GB of RAM and expected at least 2500 MB of RAM and i cant even ram some games because of not enough memory error(s).

   On same HW Win 7 64bit and Linux 64 working well - 16 GB Ram available. 

  It looks like some MSI Bios issue that some memory range on board is too huge and ignoring possibility of supported 32 bit OS! 

  Its not issue of additional components, i have only 1 additional card - GPU and have tried 3 - different cards is still same -  Geforce 1030, Geforce 220 and ATI Radeon 1300 Pro + 2 SATA - SSD + HDD discs, even BIOS is lastest.

  Info about same issue in XP part of forum:

 
 I have checked all Bios setting but i dont see anything what how possibly fix it and i havent already tried it.

Board specs details:
https://msi.com/Motherboard/X99S-SLI-PLUS.html#hero-specification

I wonder if i can fix it, by buy MB from other vendor - Asus, Gigabyte etc? Could someone try to install XP, just for RAM check, from YUMI USB flash - its just 10 minute thing... only you need switch Sata controllers to IDE mode or to some compatibility mod.

[cdob]

There was a Memory Remap Feature at previous Motherboard / BIOS. Unfortunately not at current UEFI versions.
https://forum-en.msi.com/index.php?topic=260794.0

The motherboard seems to map physical RAM 2 to 4 GB above 4 GB address space: available at 64 bit and 32 bit PAE versions.
There is no relating hint at the motherboard manual.
Strange, the manufacturer offers Vista 32 bit and later OS 32 bit drivers.
Try a BIOS update anyway.

And as a last hope, try the BIOS setting 'Windows 8/ 8.1 Configuration'.
If you are lucky, this set RAM remapping too. Do not rely on that.

[ruthan]

I have last Bios update, when i tried Windows 8/8.1 i dont see any boot device, its UEFI only i dont have right now any UEFI device, all are MBR based.

[jaclaz]

5 hours ago, ruthan said:

I have last Bios update, when i tried Windows 8/8.1 i dont see any boot device, its UEFI only i dont have right now any UEFI device, all are MBR based.

No.

If it was UEFI only, you would have not been able to boot XP on it, maybe it is one of those (stupid) UEFI that has a CSM that is automatically enabled when MBR devices are found. 

jaclaz
 

[ruthan]

I just tested Dibya PAE patch on X99 machine, its absolutely great with 920 MB - default 32 bit usable RAM from 16 GB on this MB, slow.. festival of swapping, now is pretty fast,
i didnt tested a lot of compatibility, just few games but its fastest XP with installed apps, which i had, maybe expect unsupported XP64.