TUSL2 and 256MB Memory Problem

[K2]

It would appear that my TUSL2 motherboard is having problems dealing
with any memory greater the 256MB. I have one DIMM of 256MB and two
128MB DIMMS. Any combination of DIMMS and/or slots that total greater
than 256MB of RAM cause applications to have "serious errors" and have
to close. I've downloaded memtest86 and run it against each DIMM
individually and they all pass so I believe that all three DIMMS are ok.
Anybody heard of this or have any ideas as to what I can try next to
fix or isolate the problem?
Thx
-K2

 

[K2]

It would appear that my TUSL2 motherboard is having problems dealing
with any memory greater the 256MB. I have one DIMM of 256MB and two
128MB DIMMS. Any combination of DIMMS and/or slots that total greater
than 256MB of RAM cause applications to have "serious errors" and have
to close. I've downloaded memtest86 and run it against each DIMM
individually and they all pass so I believe that all three DIMMS are ok.
Anybody heard of this or have any ideas as to what I can try next to
fix or isolate the problem?
Thx
-K2

So as a follow up, I ran memtest86 on the system with all three DIMMS in
the motherboard. Now I get an error. The first run (with the 256MB
DIMM in Slot 1) the problem was at the 136/137 and 200/201 MB point.
With the 256MB DIMM in slot 3 (and the two 128MB DIMMS in Slots 1 and
2), the error moved to the 392/393 and 456/457 MB point. Obviously the
256MB DIMM is bad. But how can it test good when it is by itself and
have a failure when in the board with other DIMMS?
Thx
-K2

 

[sdlomi]

So as a follow up, I ran memtest86 on the system with all three DIMMS in
the motherboard. Now I get an error. The first run (with the 256MB
DIMM in Slot 1) the problem was at the 136/137 and 200/201 MB point.
With the 256MB DIMM in slot 3 (and the two 128MB DIMMS in Slots 1 and
2), the error moved to the 392/393 and 456/457 MB point. Obviously the
256MB DIMM is bad. But how can it test good when it is by itself and
have a failure when in the board with other DIMMS?
Thx
-K2

Just can't resist this: Some people do not work well in a team-effort
setting--but do great as a renegade; reckon ram-sticks do the same?
Seriously, it is an interesting phenomenon, and I shall watch & hopefully
learn, along with you, the logic behind it.
BTW: What kind of ram is each of the 3 sticks? Brand-incompatability
comes to mind as well as specs-incompatability. As I understand, when we
use 1 stick of Cas 2 along with a stick of Cas 3, both sticks have to
perform, using the backward-compatability issue, at the slower rate.
Possibly, the 256 (or 128's) does not want to run at the slower rate?
sdlomi

 

[Roland Scheidegger]

So as a follow up, I ran memtest86 on the system with all three DIMMS in
the motherboard. Now I get an error. The first run (with the 256MB
DIMM in Slot 1) the problem was at the 136/137 and 200/201 MB point.
With the 256MB DIMM in slot 3 (and the two 128MB DIMMS in Slots 1 and
2), the error moved to the 392/393 and 456/457 MB point. Obviously the
256MB DIMM is bad. But how can it test good when it is by itself and
have a failure when in the board with other DIMMS?

This is quite common. With multiple dimms, the load on the memory bus is
much larger (all modules need to be driven by the same address lines -
that's why you use registered modules in servers with lots of modules).
A module might just run fine alone but won't if multiple ones are used.
In fact, there are some boards out there with 4 dimm slots on which it
is more or less impossible to get all 4 slots working at the same time
without errors unless you're very lucky (and got some really high
quality modules).
You could try to increase the dimm voltage, or use slower timinigs (or
lower frequency if that's possible with the tusl2) - but it might not help.

Roland

 

[K2]

This is quite common. With multiple dimms, the load on the memory bus is
much larger (all modules need to be driven by the same address lines -
that's why you use registered modules in servers with lots of modules).
A module might just run fine alone but won't if multiple ones are used.
In fact, there are some boards out there with 4 dimm slots on which it
is more or less impossible to get all 4 slots working at the same time
without errors unless you're very lucky (and got some really high
quality modules).
You could try to increase the dimm voltage, or use slower timinigs (or
lower frequency if that's possible with the tusl2) - but it might not help.

Roland

Roland -
The fustrating thing is that three modules ran for the better part of
a year together in this very board. I started having some file issues
(corrupted data, machine wouldn't boot, autonomous reboots, programs
crashing) so I started pulling hardware. Never found the problem (all
the hardware is back in) but can't get it to run with all three DIMMS in
the board. I'll see what I can do with the DIMM voltage and the timing
to see if that will help.
Thx
-K2