AMD64 install fails

[K. Spearel]

On Mon, 2004-06-14 at 05:16, Dr J Austin wrote:
> On Wed, 2004-06-03 at 16:25, P.Agenbag wrote
> >Hi List,
>  
> >I thought I had the problem solved, but alas...
> 
> I would be grateful if you would check out 
> bugzilla bug number 123745
> 
> It would seem to be a very similar problem that
> as far as I know has not been solved !!
> 
> John A
> 

John,

I see from your comments on this bug that you only ran memtest86 for 2
hours.  My experience is that you need to run much longer than 2 hours
to get memetest86 to reveal many memory error types on an Athlon64 as,
at least on my A64 system, the errors are due to memory timing...ie the
memory is perfectly good when run within its specifications but the
Athlon64 just doesn't like to run at high latencies.  I think AMD
tacitly admits this by specing the Opterons to only run with registered
memory...to absorb potential memory timing errors and clock skew for
maximum reliability.  

In my particular case with an Asus K8V, with the best memory timings I
could come up with for a pair of 512 Mb Samsung DIMMs, I could go for
about 8 to 10 hours running only Test 6 until I got an error.  Of
course, I could get a kernel compile to segfault just about every time
if I didn't change system settings to alleviate the problem.  So I can
say with some certainty that running the full set of tests for 2 hours
will not necessarily tell you much.

The simple fact of the matter seems to be that Athlon64s do not play
well with high latency memory.  Unless your memory is spec'd to do
2:2:2, you are apt to have problems.  I refer you to the following for
more details:

http://www.mushkin.com/epages/Mushkin.storefront/40cdb16b01a362f62740c0a801020684/UserTemplate/27

Note that this article has evolved over time but the bad news
remains...Athlon64s, with their on-chip memory controller, require fast
memory.  Even if you have memory capable of running at 2:2:2, you may
have to slow the timings down due to less than optimal trace routing on
the motherboard, power distribution problems, etc. If your problems
persist, I suggest you slow the Front Side Bus down to 167 Mhz in BIOS
and see if the problems go away...if so, then you have a decision to
make...lower performance or buying faster memory.


HTH,
KAS