Ultra 4 Plus Memory Upgrade Advice Needed

Thanks for the BIOS upgrade applet. I applied it and confirmed new BIOS version
11/02/2011 ReadyNAS-ProUltra2 V1.8

Unfortunately, the 2GB memory still doesn't POST. I installed lshw, which had this to report about the current 1MB module.
*-memory
description: System Memory
physical id: 9
slot: System board or motherboard
size: 1GB
capacity: 2GB
*-bank
description: SODIMM Synchronous 800 MHz (1.2 ns)
product: ModulePartNumber00
vendor: Manufacturer00
physical id: 0
serial: SerNum00
slot: DIMM0
size: 1GB
width: 64 bits
clock: 800MHz (1.2ns)

BIOS and Motherboard are reported as follows
readynas-1
description: Desktop Computer
product: ReadyNAS
vendor: NETGEAR
version: 11/02/2011 ReadyNAS-ProUltra2 V1.8
width: 32 bits
capabilities: smbios-2.6 dmi-2.6
configuration: boot=normal chassis=desktop uuid=00020003-0004-0005-0006-000700080009
*-core
description: Motherboard
vendor: NETGEAR
physical id: 0
*-firmware
description: BIOS
vendor: American Megatrends Inc.
physical id: 0
version: 080016 (11/02/2011)
size: 64KB
capacity: 1984KB
capabilities: isa pci pnp upgrade shadowing escd cdboot bootselect socketedrom edd int13floppy1200 int13floppy720 int13floppy2880 int5printscreen int9keyboard int14serial int17printer int1
0video acpi usb ls120boot zipboot biosbootspecification

Any additional suggestions to resolve this upgrade issue are appreciated.

Sounds like the memory you got is either bad or incompatible or both.

mdgm wrote:
Sounds like the memory you got is either bad or incompatible or both.

The RAM was certainly incompatible. Whether it was also bad is immaterial.

I finally got a single rank 2GB module, and -no surprise - it worked. The module I ended up with was a Kingston KTLTP3BS/2GB SoDIMM. One vendor told me that the Crucial part number CT25664BC1067 has no single/dual rank designation, which is why they could ship a dual rank version under the same part number. I want to thank everybody for helping me out on this journey - I ended up with a memory AND a BIOS upgrade.

So back to the Ultra 4...

I'm a bit late to the party, but my Ultra 4 is swapping too much these days and needs more RAM... sadly 4GB DDR2 SO-DIMMs are getting very hard to find (in Australia at least), so am likely going to end up getting it from overseas if I want 4GB.

There's not been much discussion about memory modules that don't work on the Ultra 4, perhaps this is because the Ultra 4 just works with most/all the 4GB modules out there? I've seen a few confirmations (Corsair, Patriot and I think G.Skill) but no particular failures with the Ultra 4. That said... I'm keen to know if anyone can confirm for the Ultra 4:

maximum memory rank?

I don't see any mention of non-working 4GB modules so am guessing it's at least 2? From this post the Ultra 4 comes with ASint DDR2 1GB 667 MHz, but the manufacturer's specs (PDF) (via here) isn't quite self-consistent and in one place says the 1GB module is always Rank 1 (table on page 1) and elsewhere says the 1GB module might be Rank 2 (page 7). Even so, its not clear if a Rank 2 module was used, so hard to be sure—is there another way of finding out the rank limits?

CAS latency limitations

Is there a min/max limit for compatible RAM modules? Does it actually even matter? Again, the original RAM data sheet claims "5-5-5" so presumably at least CL5 at 667MHz or CL6 at 800MHz should work?

Otherwise I've gathered that it supports up to 4GB in a single slot, and either 667 or 800 MHz should be OK (with no likely real-world difference between the two).

as a follow-up, in case anyone's interested...

My Ultra 4 seems happy with the G.Skill 2GB module (F2-6400CL5-2GBSQ), CL5, 800MHz, not sure if it's rank 1 or 2 (dmidecode reports the 'Memory Total Width' as 64bit which I suspect means its single rank, even though the chips are physically on both sides of the SODIMM... also note the Ultra 4 only runs it at 667 MHz according to 'dmidecode', even though both RAM and CPU support 800 MHz)

Oddly, dmidecode also reports that my maximum memory capacity is 2GB, despite others saying they've used 4GB in the Ultra 4. Not sure if this is perhaps a BIOS version issue (which is reported variously as Version: 080016, Release Date: 05/19/2010, BIOS Revision: 8.16, System Version: 05/19/2010 ReadyNAS-NVX-V2 V1.8 ) or if there's actually different hardware configurations with only some supporting 4GB, or if dmidecode is just wrong. For now though, 2GB was a lot cheaper, was actually available, and seems to have resolved my swapping-to-disk issues.

Other possibly useful info, CPU is "Intel(R) Atom(TM) CPU D410 @ 1.66GHz", which according to the specs and/or datasheet, has the memory controller built-in (no northbridge) and ought to support 4GB total RAM at 800 MHz (it looks like it supports 2 or maybe 4 ranks each up to 2GB, which is probably why no one's reported issues with any particular RAM modules not working). So I suspect dmidecode is wrong or I'm misunderstanding it.