[Beowulf] Re: Beowulf Digest, Vol 10, Issue 16

[Robert G. Brown]

On Mon, 13 Dec 2004, Mark Hahn wrote:

> > >> I believe the socket 754 and 939 Athlon 64s do not support ECC, while
> > >> the socket 940 Athlon 64 and Opteron do.
> > >
> > It's hard to tell what the 754 boards support since many say they
> > will _accept_ ECC memory but they don't say that they can actually
> > _use_ it.
> 
> all K8's support ECC - AMD definitely does not disable ECC on some chips.
> I just checked the s754 functional spec, and it certainly supports ECC.
> 
> it's conceivable that MB vendors are such twits that they'd fail to 
> detect ECC dimms and enable ECC in the bios.  it's even possible they'd
> be such idiots as to fail to connect memcheck pins to the dimm slots.

FWIW, I now am installing my ASUS K8NE, and it caims in its user guide
to support unbuffered ECC or non-ECC SDRAM (up to PC3200).

In a wee short bit I'll probably have some stream results.  I'm flashing
an upgrade from RH9 to i386 FC2 as I sit here.  However, it will take me
a few days and a reinstall to get to x64 binaries as I've got to rsync
FC x86_64 from Duke over a DSL connection, so whatever I post will be
just play.

I didn't GET ECC, BTW, because this is a home cluster box and won't be
used (I expect) for anything more than testing, benchmarks, games, and
rare production runs.

   rgb

> 
> > If you want ECC in Opterons, you need socket 940
> > Socket 939 supports 128 bit memory path, no ECC
> > Socket 754 supports 64 bit memory path, no ECC
> > Some may accept it, but will NOT be able to use it.
> 
> perhaps; I'm guessing that *ANY* lack of ECC is strictly due 
> to the bios-writer's choice.  perhaps linuxbios is salvation here.
> 
> it would actually be amusing to try doing this from within linux,
> since reconfiguring the memory controller is probably doable 
> via setpci or wrmsr.  if you try, please backup beforehand ;)
> 
> regards, mark hahn.
> 
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-- 
Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu