Upgrade BIOS ?

[Robert Heller]

At Mon, 24 Aug 2020 23:26:56 -0400 bstanle at wowway.com wrote:

> 
> 
> On 8/24/20 8:58 PM, Robert Heller wrote:
> > At Mon, 24 Aug 2020 20:42:37 -0400 bstanle at wowway.com, "Ubuntu user technical support,  not for general discussions" <ubuntu-users at lists.ubuntu.com> wrote:
> >
> >>
> >> On 8/24/20 6:11 PM, Chris Green wrote:
> >>> On Mon, Aug 24, 2020 at 10:39:23AM -0400, Bill wrote:
> >>>> Hi,
> >>>>
> >>>> Are there any side effects of upgrading the BIOS on my computer? The
> >>>> computer is quite old but it is arguably still a good machine (i7 with 12 GB
> >>>> ram but it still has the original BIOS - circa 2010).  Is Linux affected in
> >>>> any way (both positive or negative)?
> >>>>
> >>> Is there any particular reason that you want to upgrade the BIOS?  If
> >>> there isn't then I think I'd leave well alone, it's unlikely to give
> >>> you any useful new facilities or speed anything up at all.
> >>>
> >> WS=> That is what I think as well!  I just wanted to know what the
> >> opinion of others was.
> > Generally with the BIOS it is often a case of "If it ain't broke, don't fix
> > it."
> >
> > Linux actually makes very little use of the BIOS, once the kernel starts up.
> > Messing with the BIOS is mostly a matter of what happens between applying
> > power and the kernel start. The usual reasons for upgrading the BIOS might
> > relate to dealing hardware that the BIOS needs to initialize and the usual
> > hardware that might get added is a newer processor or newer (bigger) disk
> > drives, since these are really the only hardware that you can add that the
> > BIOS needs to know how to deal with -- things like PCI cards usually provide
> > their own firmware ROMs. Oh, there might be issues like memory size limits --
> > I guess it is possible that a newer BIOS might be needed if you install larger
> > RAM sticks than the original BIOS supported -- I'm not totally sure about
> > that.
> 
> WS=> Ahh!  You are getting to the meat of the matter.
> 
> My computer came with 8 GB installed and the users manual says it could 
> be upgraded to 16 GB.  At the time, I thought the memory was in a single 
> 2 dimm bank for 2X4GB.  I ordered 2 8GB dims and upon opening the case 
> to replace the memory, I discovered 2 dimm banks (for a total of 4 
> slots.  The second bank was partially hidden).
> 
> I put the new 8 GB memory in one bank and left the other bank as it 
> was.  The BIOS is recognizing the new 8 GB dimms as 4 GB dims. The 
> computer works OK but with the new 8GB in the first bank and 4 GB in the 
> other bank (for a total of 12 GB).  Do you think that a BIOS upgrade 
> might get the computer to see the two 8 GB dimms. This would get the 
> computer to recognize more than the original 16 GB. limit.

There might be limitations on the number of address bits wired to the memory 
connectors.  Or limits based on the physical address space of the partitular 
processor.  Updating the BIOS is not going to do anything about that.

The problem you are see might be because the *hardware* requires the memory 
dimms to be "matched" -- all of the dimms in a given bank have to be the same 
size.  I think some of the early 64-bit motherboards took 32-bit dimms and 
built a 64-bit bus from pairs of dimms, so if the pair bank had different 
sized dimms, the smaller size determined the size of the pair, since the 
memory test would fail on 1/2 of the longword beyond the small dimm's 
capacity. 

> 
> PS. I might have not explained the arithmetic properly.
> 
> Bill Stanley
> 
> 
> 
>                                                                                                      
> 

-- 
Robert Heller             -- Cell: 413-658-7953 GV: 978-633-5364
Deepwoods Software        -- Custom Software Services
http://www.deepsoft.com/  -- Linux Administration Services
heller at deepsoft.com       -- Webhosting Services