I suggest that you:
1) download a copy of Memtest86
(Google to find a reputable site to download a copy),
this is a memory diagnostic program,
burn a copy to CD
2) restart your machine with the Memtest86 CD in the
3) look for the option in the program that evaluates
and diagnoses the memory architecture.
That will identify the CLxx (latency) of the internal
The latency of the internal and external (new) RAM
If they do match, then the issue must be with the
design/operation of the upgrade(new) memory modules
- in that case you will be out of luck.
Insert your upgrade RAM module and repeat steps 1-3
above to see if Memtest86 can recognize the presence
of the modules (highly unlikely if the BIOS cannot
recognize their presence)
Apart from that (and this is a long shot in the dark)
ensure that when you insert the modules that the
edge contacts are bright and clean (do NOT rub any
fabric across them!!! - that could be destructive),
and that the module is making snug and correct
contact in it's socket when installed.
I'm sorry to say, there is not much more I can think
of to suggest. If you have ruled out that the modules
are ok, the machine is ok, the memory speed is
compatible (check) and right voltage (check), that
the latencies match(*1), and the architecture of the module
matches the machine's physical,timing,and signalling
requirements then it it pretty much game over.
Time to look for alternative memory modules.
Note: (*1) "In theory" in most implementations you can
mix memory modules of differing latencies
(within reason/limits). If the modules mismatch
then the memory access should default to the access
speed allowed by the lowest latency module.
As I said "in theory". In "practice" some machines
are particular that the latency of all modules
match and that the latency is of a specific value.
(some old HP laptops with DDR were a specific
example of this - accepting only one type of
module full stop - argh
I downloaded a copy of the user manual - no
useful information about the memory modules there.
Some suppliers on the www are quoting both CL5 and
CL6 spec modules as compatible.
I still think a word to ASUS is the best approach
to determine the exact module requirements before
sourcing any further modules.
Best of luck
I had a look at the latest offered BIOS update.
No mention in the revision history of any changes
to memory management (didn't expect to find any
though). I strongly recommend that you avoid
updating the BIOS unless: ASUS recommend it as a
critical update, or the update contains a
modification that is essential for your use.
There is always a risk of converting a perfectly
good machine into a useless "brick" should a
BIOS update process fail.