Re: [coreboot] 16GB dimm on Sandy/Ivy Bridge status

[Patrick Rudolph]

Hi Iru,
> From T420 manual [1]:

"Memory: Up to 8GB DDR3 - 1333MHz (2 DIMM Slots)"

While it seems possible to use 16GB (2x 8GB), it isn't possible to use
16GB DIMMs.
I haven't tested by myself, but it seems like a hardware limitation.
Please provide raminit logs, just to make sure.

Regards,
Patrick

[1]
http://www.lenovo.com/shop/americas/content/pdf/notebooks/ThinkPad/t-series/...

On 2016-05-31 05:04 AM, Iru Cai wrote:
> Hi,
>
> I'm tesing to see if the coreboot Sandy/Ivy MRC supports 16GB DIMMs.
> Here's my result.
>
> I'm using a MT16KTF2G64HZ-1G6A1[1]. My machine is Lenovo T420 with
> i7-3630QM. With this module inserted (I've tested 16G+0 and 16G+8G),
> the system can light up, but it'll then get crashed.
> with GRUB2 payload, it'll crash after the payload loads
> with SeaBIOS payload with proprietary VGABIOS, I can see the prompt,
>
> and can boot to a GRUB or syslinux loader on my USB stick, but when I
> try to boot a system, it get crashed. If I boot to Memtest86+ on my
> USB stick, the system will crash when memtest starts to test the
> memory.
>
> And another thing I can see is, the first boot can boot to payload,
> but the second boot will fail. I think it's caused by the MRC cache.
>
> I'm still wondering if Sandy/Ivy northbridge can support 16GB DIMMs.
> I'll give a more detailed EHCI debug output later. According to [2], I
> think the incompatibility is an MRC issue instead of hardware
> incompatibility.
>
> [1]
> https://www.micron.com/parts/modules/ddr3-sdram/mt16ktf2g64hz-1g6?pc=%7BE1D8...
> [2]
> http://www.intelligentmemory.com/fileadmin/download/compatibilitylist.pdf
>
> Iru.

16GB dimm on Sandy/Ivy Bridge status

[Stefan Tauner]

On Tue, 31 May 2016 07:07:46 +0200
Patrick Rudolph  wrote:
> Hi Iru,
> From T420 manual [1]:
> "Memory: Up to 8GB DDR3 - 1333MHz (2 DIMM Slots)"
>
> While it seems possible to use 16GB (2x 8GB), it isn't possible to use
> 16GB DIMMs.
> I haven't tested by myself, but it seems like a hardware limitation.
> Please provide raminit logs, just to make sure.

Hi,

it is often not but the manuals are just reflecting what the vendor has
tested. Very often these test are not extended once bigger DIMMS become
available hence the documentation is not reliable at all. The only
hardware limitation I am aware of that could interfere is what the
northbridge supports...
http://ark.intel.com/products/52229/Intel-Core-i5-2520M-Processor-3M-Cache-u...
So unlike the manual (the "Up to 8 GB" are meant as total) 16 GB is the
maximum. The question remains if a single channel can address the whole
range but given that it does not make sense economically that point is
rather moot anyway.