RE: In search of bad 4164, 41256 DRAM

From: Jeffrey Birt <*birt_j_at_soigeneris.com*> Date: Sat, 14 Sep 2019 08:23:09 -0500 Message-ID: <003f01d56aff$8df758e0$a9e60aa0$_at_soigeneris.com> · birt_j_at_soigeneris.com

Respectfully, I'm interested in testing 40 year old nKx1bit DRAM chips not
modern DDR memory modules...

Jeff Birt

-----Original Message-----
From: smf <smf_at_null.net> 
Sent: Saturday, September 14, 2019 7:15 AM
To: cbm-hackers_at_musoftware.de
Subject: Re: In search of bad 4164, 41256 DRAM

On 14/09/2019 11:46, Gerrit Heitsch wrote:
> DDR4 should be less problematic than DDR3 since they included a 
> feature called 'Target row refresh'. Doesn't seem to result in full 
> immunity though.
Some DDR3 modules support pseudo target row refresh when used with certain
chipsets.

TRR also isn't part of the DDR4 standard, it's up to manufacturers to decide
whether they wish to support it & if it's not standardised then it's hard to
know if the implementation is the same and how effective it is.

https://arstechnica.com/information-technology/2016/03/once-thought-safe-ddr
4-memory-shown-to-be-vulnerable-to-rowhammer/

It's a three year old article, but there are probably plenty of three year
old memory modules out there.