Re: [opensuse] Adding RAM / Voltage adjustment? On Thu, Feb 28, 2008 at 1:45 PM, Felix Miata  wrote:
> On 2008/02/28 13:12 (GMT-0500) Greg Freemyer apparently typed:
>
>
>  > We've been struggling with a couple of our machines that were
>  > attempting to add memory to.  (ie. 2GB -> 4GB)
>
>  > The machines were just not stable after the upgrade.  Assumed it was a
>  > Video Card logic issue, etc.
>
>  > Someone just told us that it is typical that the BIOS voltage setting
>  > for the memory bus has to be tweaked as you add RAM.
>
>  > ie. Lower for small amounts of RAM.  Higher for bigger amounts.
>
>  > This is really strange to me, but we have adjusted those 2 machines
>  > and they are seemingly running fine now.
>
>  > Is this really a typical thing to have to do?
>
>  It's not uncommon in my experience with DDR. I've often needed 2.6v instead
>  of 2.5v, and in one case, 2.7v instead of 2.5v. I don't think the amount of
>  RAM populating the board has anything to do with it. Did you test with the
>  new RAM only? Did you use memtest86+ for several passes? Some RAM simply
>  needs more voltage than the standard motherboard spec. If you note while
>  shopping around for RAM, some RAM specs list higher than nominal, like 2.6v
>  where 2.5v is otherwise expected. Is the added RAM an exact match for your
>  existing RAM, same brand and chip stampings?

In our case all 4 sticks were bought together in an effort to get
things stable.  2 at a time was stable.  4 was not.

Just did a little googling and I do see people saying they are having
to adjust voltages to get 4 1GB sticks to work.

One of the threads I found said the issue was fixed by adjusting the
Northbridge voltage instead.

FYI: I have not been working on this personally, so I may have the
details of wht voltages are tweaked wrong.

Anyway, it is rather strange, but I guess in the 4GB world you need to
be prepared to do some MB BIOS voltage and timing tweaking.

Just this morning we were discussing what MB to use for future
systems.  We're looking at going back to Intel.  I wonder if they have
this problem too.

Anyway, one more reason to standardize on a MB.  Don't want to have to
learn this sort of thing over and over again.

Greg
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