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Windows 7: BIOS battery backup issue...

21 Sep 2012   #1

Windows 7 64-bit
BIOS battery backup issue...

AFAIK, the purpose of the BIOS battery backup is to provide power to the BIOS chip for storing the BIOS setting when the computer is shutdown. It seems that on my machine, it no longer functioning as it should.

Starting up the desktop stops at the BIOS screen that asks for running setup or take the default values for the BIOS settings. Selecting the default values does boot Windows, but it also detected lot of changes and my drives, including the SSD, show up now as IDE/ATAPI interfaces. Windows did ask for reboot that didn't take place as of yet and everything seems to be working just fine.

The question is, will the unintentional change from AHCI to IDE have any issues when the system is rebooted? If the machine will boot just fine, can the BIOS settings changed back to AHCI? I seem to recall that there might be an issue with Windows when changing the hardware control type in the BIOS.

My System SpecsSystem Spec

21 Sep 2012   #2

Microsoft Community Contributor Award Recipient

Windows 7 x64

It sounds as if the battery is dead.
It's not going to save any settings properly in that state, you should try swapping out the battery it's only 3 or 4 bucks.

I've seen this battery die on computers ranging from days to a decade old.
generally they do last several years without trouble though.
My System SpecsSystem Spec
21 Sep 2012   #3

Windows 7 64-bit

Thanks Magus...

It seems that shutting off the power strip for the machine and accessories caused the battery to die "prematurely".

The question is, will the rebooting have any issues?
My System SpecsSystem Spec

21 Sep 2012   #4

Microsoft Community Contributor Award Recipient

Windows 7 64 Bit Home Premium SP1

You need to reboot and complete the installation of the "new" drivers. You will only complicate the upcoming repairs if you do not.

Once you have got the battery/BIOS issue resolved you will boot into Windows and then prepare to switch back to AHCI mode in BIOS as here:

AHCI : Enable in Windows 7 / Vista
My System SpecsSystem Spec
21 Sep 2012   #5

Windows 7 64-bit

I did reboot and the machine seems to be OK in IDE mode. The SSD and and the external eSATA drive are connected to the Marvel controller (SATA III) and show up as SCSI disk drives, the same as under AHCI. The four internal SATA HDDs show up as ATA devices.

The machine seems to be slower than used to be, or I'm just paying more attention to it. The updated WEI score in all categories is the same as it's been under AHCI.

Since TRIM is not supported by the Marvel controller, the SSD drive has GC, there seems to be no reason to switch back to AHCI. I'll run the machine in IDE mode until the BIOS battery is replaced. I've never experienced a BIOS battery dying ever, much less on the Asus MB...

Thanks guys for you help...
My System SpecsSystem Spec
21 Sep 2012   #6
Microsoft MVP

Win 7 Ultimate x64


Name:  cr2032.jpg
Views: 136
Size:  5.4 KB

is what you need and can be bought anywhere watch batteries are sold.

My System SpecsSystem Spec
21 Sep 2012   #7

Windows 7 64-bit

Thanks Stormy...
My System SpecsSystem Spec
21 Sep 2012   #8

Windows 7 64-bit

Actually, I've ended up getting a DL2032 battery, which is the same as the CR2032.

Instead of using the CR letters, lithium(C) shape(R), Duracell marks theirs as Duracell(D), Lithium(L). The 2032 indicates the size and voltage of the battery (O.D 20mm, W 3.2mm, 3V), with polarity marked on top.

One more thing that I didn't want to or need to learn
My System SpecsSystem Spec
21 Sep 2012   #9

Microsoft Community Contributor Award Recipient

Windows 7 64 Bit Home Premium SP1

But we learned it too! Lithium batteries - nice!
Thanks for the info.
My System SpecsSystem Spec
23 Sep 2012   #10

Windows 7 64-bit

Unfortunately, I am still learning...

If I shutdown the computer, it starts up just fine as long as the power strip feeding my gear is kept on.

If I shutdown the computer and flip the switch on the power strip, the BIOS does not retain its settings. The power strip feeds the PC, the monitor, eSATA drive, network switch, and speakers. It seemed simpler to kill the the power for all, instead of individually shutting down everything.
Upon boot, the screen shows:

Please enter Setup to recover BIOS setting

Press F1 to run setup
Press F2 to continue with default setting
Pressing F1 and entering the setup shows the correct time/date and all of the devices are detected. AFAICS, these are the settings that are changed:
  1. Storage type: ACHI to IDE
  2. Boot order: Disk 5 to Disk 0
Note: The SSD is connected to the Marvell chip and shows up as Disk 5 in Windows. Disk 0 is the HDD connected to on board SATA II port 0.

Change the boot order, save settings, and Windows boots just fine, albeit a bit slower than with ACHI settings. Once in Windows, the system runs just fine without noticeable performance decrease. The AHCI had not been enabled yet to prevent Windows going bunkers with "Found new devices..." and reboots.

I did flush the BIOS to the latest version, but that did not make any difference. When the power is killed after shutting down the PC, the BIOS settings are not retained.

About six month ego, the BIOS did loose the boot order settings couple of times. Instead of entering setup, pressing F8 and selecting the SSD drive (Drive 5) to boot had fixed the problem then.

In retrospect, it seems that the Asus motherboard BIOS is progressively getting worse; the next phase may even be no post whatsoever. Other than changing the motherboard, is there anything else that could be done to revive this POC?

I hate learn about the BIOS... especially on my own system...
My System SpecsSystem Spec

 BIOS battery backup issue...

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