Question on DDR Ram problem

  • Thread starter Thread starter Lawrence Guros
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Lawrence Guros

Hi, I have a funny problem on my eMachines (FIC AM39L motherboard, Via
KM400A chipset) with memory.

I recently got 512MB Kingston memory to add to my 512MB Samsung memory
that came with the system.

I put the Kingston in the first slot, and the Samsung in the second, and
my system was flaky.

I switched them, and my system was stable, but I wanted to make sure and
got MEMTEST-86.

With 1 gig installed, I am getting a few errors on test 5 (never the
same amount, and never at the same place).

With either chip in the first slot, I get no errors at all!!!!!

Is there a way I can diagnose what is going on? Could the extra memory
be dragging down the amount of power causing the problem?

Or what else could be the problem? The system seems stable enough now,
but I am not very comfortable with MEMTEST-86 failing (only on test 5).

Thanks for any advice,
Larry
 
Hi, I have a funny problem on my eMachines (FIC AM39L motherboard, Via
KM400A chipset) with memory.

I recently got 512MB Kingston memory to add to my 512MB Samsung memory
that came with the system.

I put the Kingston in the first slot, and the Samsung in the second, and
my system was flaky.

I switched them, and my system was stable, but I wanted to make sure and
got MEMTEST-86.

With 1 gig installed, I am getting a few errors on test 5 (never the
same amount, and never at the same place).

With either chip in the first slot, I get no errors at all!!!!!

Is there a way I can diagnose what is going on? Could the extra memory
be dragging down the amount of power causing the problem?

Or what else could be the problem? The system seems stable enough now,
but I am not very comfortable with MEMTEST-86 failing (only on test 5).

Thanks for any advice,
Larry
Click to expand...

If the 2 sticks of ram don't have the same timings you'll probably need
to set them manually in the BIOS to the slower stick of ram.
Common settings...
CAS Latency
RAS to CAS Delay
RAS PreCharge Delay
Active PreCharge Delay
Command Rate

Memory Basics
http://www.corsairmicro.com/memory_basics/153707/index.html

FIC AM39L motherboard manual
ftp://ftp.fica.com/manuals/motherboards/Socket%20A/AM39L/

Ed
 
Lawrence Guros said:
Hi, I have a funny problem on my eMachines (FIC AM39L
motherboard, Via KM400A chipset) with memory. [snip]
I switched them, and my system was stable,
Click to expand...

Very typical for different memory ratings. AFAICS, the
chipset only reads one DIMM EEPROM for it's settings.
Is there a way I can diagnose what is going on? Could the
extra memory be dragging down the amount of power causing
the problem?
Click to expand...

Entirely possible that it is bus loading. First try
manually changing all memory settings to their slowest.
If memtest is clean, reset half faster. If not, replacing
the PSU _might_ help, but most likely it is a poor mobo or
mem modules.

-- Robert
 
Hi, I have a funny problem on my eMachines (FIC AM39L motherboard, Via
KM400A chipset) with memory.

I recently got 512MB Kingston memory to add to my 512MB Samsung memory
that came with the system.

I put the Kingston in the first slot, and the Samsung in the second, and
my system was flaky.
Click to expand...

All DRAM from different mfrs has slightly different tolerances on timings -
especially with large amounts, like 1GB, it's a bad idea to mix. Do you
know the timings on the Samsung?
I switched them, and my system was stable, but I wanted to make sure and
got MEMTEST-86.
Click to expand...

In your BIOS Setup, are the timings all set to use SPD? A good BIOS should
examine SPD of all modules and use the slowest combined timings, or if the
chipset supports separate individual timings apply them... but many don't
get it quite right. Some will even report the values on the POST screen.
With 1 gig installed, I am getting a few errors on test 5 (never the
same amount, and never at the same place).
Click to expand...

I've seen a few failures on test 5 when timings were too tight - start by
pushing up tRCD and then CL. Get memtest86+ from www.memtest.org and it'll
show the actual timings being used. The conventional order is CL - tRCD -
tRP - tRAS - xT, typically 3-3-3-8-2T. From what I've seen, the command
rate, 1T or 2T, has the most effect on bandwidth performance on current
DIMMs.
With either chip in the first slot, I get no errors at all!!!!!

Is there a way I can diagnose what is going on? Could the extra memory
be dragging down the amount of power causing the problem?
Click to expand...

Yep that's likely the problem - the memory channel is more "loaded". It
could be that your different DIMMs require different voltages too -
Kingston seems to specify higher, up to 2.7V - for their faster DIMMs. If
you can adjust voltage in BIOS try bumping that, to a max of say 2.75V, as
well as relaxing timings.
Or what else could be the problem? The system seems stable enough now,
but I am not very comfortable with MEMTEST-86 failing (only on test 5).
Click to expand...

That's not unusual. Get Prime95, from http://www.mersenne.org/freesoft.htm
which runs under Windows and run the "torture test"... for a good hour or
more. It often finds errors when memtest86 or memtest86+ has not - in my
testing this happened with command rate at 1T and pushing it to 2T "fixed"
things.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??
 
I just got another stick of Kingston ram for my Emachines w2785 with the AM39l. It doesn't seem to like my computer though. I thought maybe it was just my computer but I can't even see my Dram timings in the bios. The ram is kingston pc3200 with a cas latency of 3 and my other samsung ram is cl2.5. I tried the ram again and it seems to be running ok now. The only thing I changed was the memory hole. I put that on the 15-16m setting.
 
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