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Acer Aspire XC-605 BIOS Help.

ChuckoChucko Posts: 7Member New User
Hi there everyone, so I have a Acer Aspire XC-605 and im wishing to update the BIOS as I believe my new RAM is not working because of this issue. the RAM is compatable with this board has been checked. My current bios is version P11-A1. Now when I look BIOs Firmware on acer site there are a few different options the most recent P11-B4L or there is also P21.A4 but is slightly older normally i would just do the newest one but have read that P21.A4 could be better. bit confused. i have downloaded both and read the read me files however the english in them is very poor, english is not my first language but i still struggled to understand them. 

any help would be great thanks.

BIOS page 


  • JordanBJordanB Posts: 3,448ACE Pathfinder
    edited February 2019
    Hello Chucko,

    I'll give you instructions for updating the BIOS to the latest P11.B4.  

    I think you should check your existing memory and see if it is DDR3L 1.35 V or DDR3 1.5 V.  It will be written on the label on your memory.

    If your existing memory is 1.5 V, I would recommend the Kingston memory below.  Try to match the same 1.35 or 1.5...whichever you have.


    In theory, it shouldn't matter mixing DDR3 and DDR3L on your xc-605 desktop mainboard, but I remember someone else had a problem mixing for some unknown reason when using DDR3L Crucial memory on their XC-605.  If you're in doubt, I would recommend the Kingston memory.

    Here's instructions for updating your BIOS, but I don't think that's really your problem. 

    The standard operating procedure (SOP):


    1. Download P11.B4

    2. Extract

    3. Copy the Win and ROM folders to a USB flash drive.

    4. Open an admin command prompt

    5. If your USB flash drive has a drive letter of F, then you would type


    cd win



    6. After the processing completes, restart your computer

    7. When it prompts you to enter the BIOS, press the "delete" key on your keyboard to enter the BIOS settings

    8. Load the BIOS defaults (F9) and then save/exit (F10).

    I'm not an Acer employee.
  • ChuckoChucko Posts: 7Member New User
    your right they are different voltages my new ram is 1.5 and the ram in my pc is 1.35. take it this board cant take 1.5. damm
  • JordanBJordanB Posts: 3,448ACE Pathfinder
    edited February 2019

    Your mainboard should work at either 1.35V or 1.5V.    But for whatever reason, it doesn't like mixed ram.  If you install two 1.35V DDR3L modules, it will work fine.   If you install two DDR3 1.5V modules it will work fine.    DDR3L is supposed to run at 1.35 or 1.5, but for whatever reason, your mainboard/UEFI doesn't like mixing DDR3 and DDR3L.

    My mainboard is running 1.5V DDR3.  (I have TC-605 which uses the same mainboard as XC-605)
    I'm not an Acer employee.
  • ChuckoChucko Posts: 7Member New User
    hmmmm i dont know then as ive tried the 1.5v ram on its own and does not work either, fans go into turbo mode and just black screen. which is why i thought it could be the old bios.
  • JordanBJordanB Posts: 3,448ACE Pathfinder
    It could be just a matter of pulling out the CMOS battery for a couple hours and resetting BIOS.  But I don't want to waste your time with guesses.  If your computer came with 1.35V, it's probably best to just return the 1.5V and get some 1.35.
    I'm not an Acer employee.
  • JordanBJordanB Posts: 3,448ACE Pathfinder
    If I remember correctly, if you install a single stick of ram, you must put in the slot closest to the CPU
    I'm not an Acer employee.
  • ChuckoChucko Posts: 7Member New User
    wont be able to return now i dont think it was brought as a gift before christmas on amazon i think. could try the battery and bios, when you say reset BIOs do you mean update to P11.b4
  • JordanBJordanB Posts: 3,448ACE Pathfinder
    If you unplug the computer from the elctrical outlet, and pull out the CMOS battery for a couple hours, it will reset the BIOS.   I wasn't talking about updating the BIOS.
    I'm not an Acer employee.
  • ChuckoChucko Posts: 7Member New User
    could this not cause some boot issues if done incorrectly say?
  • JordanBJordanB Posts: 3,448ACE Pathfinder
    If you're not comfortable.........It might be best to just try to sell your 1.5V memory on ebay.  And then get the 1.35V in link below.

    I'm not an Acer employee.
  • HelpMe35HelpMe35 Posts: 11Member


    To Flash it. Simply unplug your machine and take out the battery. Hold power for 30 seconds, plug machine in, hold fn+esc, press power,  let go of fn +esc after machine starts.

    To create USB.  Open cmd as admin. 
    List disk
    Select disk "your disk number no quote "
    Create partition primary 
    List partition 
    Select partition "your partition number"
    Format fs=fat size=4000 quick 

    Download the Acer bios from drivers and downloads, extract the exe,  and place the contents on the USB

    NOTE: If you try to do the wrong version; and keep holding FN+ESC, you will enter efi shell where you can load EFI protocols and device drivers, and execute simple scripts. 
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