[coreboot] More details about ram issues

Nico Huber nico.h at gmx.de
Fri Nov 11 23:37:20 CET 2016

On 11.11.2016 17:12, Patrick Rudolph wrote:
> Am Fri, 11 Nov 2016 13:53:16 +0100
> schrieb Nico Huber <nico.h at gmx.de>:
>> On 11.11.2016 08:14, Charlotte Plusplus wrote:
>>> I do not know how to adjust the voltage (it should require talking
>>> to the IMC of the CPU)  but I think that as soon as this is done,
>>> stability should improve.
>>> If someone can propose a patch doing that (either using the voltage
>>> read from SPD, or by manually entering voltage information), I will
>>> be happy to test it.  
>> Depending on the board the voltage might not be configurable at all.
>> Why should it be if there is only one voltage defined in the standard?
> The W520 does only have 1.5V DDR voltage. If it's stable with vendor
> bios, it's not a DDR voltage problem at all.

That's what I suspected, too.

>>> For now, I urge caution when operating even at DDR-1866
>>> frequencies. Most boards do set up 933 as their max_mem_clock_mhz.
>>> It is not very prudent to do that until the voltage situation can
>>> be solved.  
>> If the board can work at that frequency, that's just fine. If the
>> voltage is a problem, it's due to the memory module. IMHO, the rule
>> should be to ignore SPD frequency settings that include an out of spec
>> voltage.
> That's what sandybridge raminit does. Only XMP profiles with DDR
> voltage of 1.5V are used. Profiles that do have other voltage
> setting are ignored.

Good to know, I already started worrying about your code just by reading
emails. Should have looked in the code instead ;) my apologies.


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