"csm" said:
I have a new ASUS A8N-SLI Premium MB with 1 gig (2x512MB 400MHz -
TWINX1024-3200C2PT) of Corsair XMS Platinum series DDR. The memory is
installed in the A-1 & B-1 slots. Everything works OK. However, when I add
a second gig of Corsair non-Platinum series (2x512MB 400MHz -
TWINX1024-3200C2) DDR memory to the A-2 and B-2 slots, the system will not
boot and the screen stays off. I have also paired the Platinum Series
memory to A-1 & A-2 and Non-Platinum series to B-1 & B-2 with no success.
Any ideas?
CM
Try a pair of DIMMs in A1-B1 and check that the BIOS
reports dual channel and all (1GB) of memory is reported.
Repeat for A2-B2 slots.
The purpose of doing this, is to rule out a bad DIMM slot
or a bad chip select signal on the processor memory controller.
I've read a few posts now, where the Asus BIOS is using
a riduculous set of criterion for DIMM matching. I do seem
to remember reading somewhere, that they wanted four
identical DIMMs, but identical according to AMD, is to
match rows, columns, banks, and ranks. I think AMD also
wanted the same CAS for each DIMM, but I don't see that
as being a necessary requirement (previous motherboards have
survived quite nicely by selecting the slowest DIMM, to set
the timing on the controller). Document 26094 on the
AMD site contains all you could ever want to know about
"BIOS Writers guide" to the Athlon64 family, and Asus
doesn't seem to be doing exactly as the guide suggests.
It could be that this is one of those matching problems. Now,
in your case, if I go to the corsairmicro.com website, and
download datasheets for your two pairs of DIMMs, of course
they have the exact same specs. They are only supposed to
differ in the heat spreader on the module. However, you should
still get a copy of CPUZ from cpuid.com , and dump the
contents of each DIMM's SPD, and see to what extent the DIMMs
are the same. One DIMM will have a product name with the
word "Platinum" in it, which is a difference, but Asus should
not be comparing vendor strings on all four DIMMs for a
match.
In one case I read about, similar to your module choices,
the poster could not get the second set of DIMMs to be
seen by the BIOS. Only one pair would register and be
counted during the BIOS RAM test. Your symptoms are
a bit different than that, but it is the same issue, with
a crappy decision tree in the BIOS when dealing with
four DIMMs.
Other reauirements are, if operating at DDR333, then command
rate 1T timing should be OK. If operating at DDR400 with
your four DIMMs, then command rate 2T should work. DDR400 2T
is slightly faster than DDR333 1T. In one of the Anandtech
articles for the A8V Deluxe (an earlier board), they found -
"The A8V Deluxe is also very picky about the settings that
are used with 4 dimms in the 'Enable 2T' option in BIOS.
If an Auto setting is used with 4 dimms the board tries to set
1T and single channel memory at a lower memory speed. If 'Auto'
is selected and memory timings are forced to DDR400 the board
would not boot. With 4 dimms, you will need to set the 2T
option to 'Enable 2T' for proper Dual-Channel operation
at DDR400."
Perhaps your BIOS has the same bug ? Try setting the Enable 2T
option so the BIOS has no choice but to use 2T timings, before
installing the second set of sticks. Maybe that will coax some
life from it.
Paul
