[gentoo-user] The memory gremlin

[gentoo-user] The memory gremlin

[Alan Grimes]

[resend, list was down...]

I've been meditating on the memory gremlin on my system...

The ram is Corsair, 3000mhz. (never had any problem with their sticks in
any system ever.)

Motherboard is an early release mini-ATX B350 board from Asus...

Chip is a R7 1800X

The pattern is: all cells test good on memcheck but occasionally there
is a bit error somewhere. I think it is a signaling issue between the
ram module and the memory interface in the cpu.

After meditating on it, I don't think there's anything I can do about it
given the STUPID settings the BIOS goes to... The problem with the BIOS
is that it considers only what the RAM tells it, it does not take into
account that the CPU is rated at 2667mhz... Well there's the answer,
this is AMD's first product with DDR4 support, and it's not super
awesome so simply acknowledging the limitation there, and setting the
memory interface to 2666 (which is what the BIOS offers), it won't be
super fast but it damn well should work. =|

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Re: [gentoo-user] The memory gremlin

[Mick]

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On Thursday, 9 August 2018 17:32:33 BST Alan Grimes wrote:
> [resend, list was down...]
> 
> I've been meditating on the memory gremlin on my system...
> 
> The ram is Corsair, 3000mhz. (never had any problem with their sticks in
> any system ever.)
> 
> Motherboard is an early release mini-ATX B350 board from Asus...
> 
> Chip is a R7 1800X
> 
> The pattern is: all cells test good on memcheck but occasionally there
> is a bit error somewhere. I think it is a signaling issue between the
> ram module and the memory interface in the cpu.
> 
> After meditating on it, I don't think there's anything I can do about it
> given the STUPID settings the BIOS goes to... The problem with the BIOS
> is that it considers only what the RAM tells it, it does not take into
> account that the CPU is rated at 2667mhz... Well there's the answer,
> this is AMD's first product with DDR4 support, and it's not super
> awesome so simply acknowledging the limitation there, and setting the
> memory interface to 2666 (which is what the BIOS offers), it won't be
> super fast but it damn well should work. =|

Keep an eye on MoBo firmware updates, Asus are usually OK in providing updates 
to stabilise their chipsets, as long as the bugs are fixable in software.

Also, if the BIOS offers DRAM timing settings increase the latency a notch and 
see if that helps.

-- 
Regards,
Mick

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Re: [gentoo-user] The memory gremlin

[Bill Kenworthy]

On 10/08/18 02:00, Mick wrote:
> On Thursday, 9 August 2018 17:32:33 BST Alan Grimes wrote:
>> [resend, list was down...]
>>
>> I've been meditating on the memory gremlin on my system...
>>
>> The ram is Corsair, 3000mhz. (never had any problem with their sticks in
>> any system ever.)
>>
>> Motherboard is an early release mini-ATX B350 board from Asus...
>>
>> Chip is a R7 1800X
>>
>> The pattern is: all cells test good on memcheck but occasionally there
>> is a bit error somewhere. I think it is a signaling issue between the
>> ram module and the memory interface in the cpu.
>>
>> After meditating on it, I don't think there's anything I can do about it
>> given the STUPID settings the BIOS goes to... The problem with the BIOS
>> is that it considers only what the RAM tells it, it does not take into
>> account that the CPU is rated at 2667mhz... Well there's the answer,
>> this is AMD's first product with DDR4 support, and it's not super
>> awesome so simply acknowledging the limitation there, and setting the
>> memory interface to 2666 (which is what the BIOS offers), it won't be
>> super fast but it damn well should work. =|
> Keep an eye on MoBo firmware updates, Asus are usually OK in providing updates 
> to stabilise their chipsets, as long as the bugs are fixable in software.
>
> Also, if the BIOS offers DRAM timing settings increase the latency a notch and 
> see if that helps.
>
If you can locate it to a location range, you can use a kernel argument
to exclude that area of memory.  The hard part is to map the range.  Had
one system running that way for years.

BillK