I was thinking about upgrading my laptop's RAM. It currently has a 4096 MB module and a 2048 MB module, which I thought I could replace by an 8 GB module:
[root@...] # dmidecode -t 17 # dmidecode 2.12 SMBIOS 2.6 present. Handle 0x001E, DMI type 17, 28 bytes Memory Device Array Handle: 0x001D Error Information Handle: Not Provided Total Width: 64 bits Data Width: 64 bits Size: 4096 MB Form Factor: SODIMM Set: None Locator: ChannelA-DIMM0 Bank Locator: BANK 0 Type: DDR3 Type Detail: Synchronous Speed: 1333 MHz Manufacturer: Samsung Serial Number: 946CAE2D Asset Tag: 9876543210 Part Number: M471B5273CH0-CH9 Rank: Unknown Handle 0x0020, DMI type 17, 28 bytes Memory Device Array Handle: 0x001D Error Information Handle: Not Provided Total Width: 64 bits Data Width: 64 bits Size: 2048 MB Form Factor: SODIMM Set: None Locator: ChannelB-DIMM0 Bank Locator: BANK 2 Type: DDR3 Type Detail: Synchronous Speed: 1333 MHz Manufacturer: Samsung Serial Number: C18B2141 Asset Tag: 9876543210 Part Number: M471B5773DH0-CH9 Rank: Unknown
But then I looked at the Physical Memory Array and discovered that, apparently, the maximum RAM capacity is 8 GB:
[root@...]# dmidecode -t 16 # dmidecode 2.12 SMBIOS 2.6 present. Handle 0x001D, DMI type 16, 15 bytes Physical Memory Array Location: System Board Or Motherboard Use: System Memory Error Correction Type: None Maximum Capacity: 8 GB Error Information Handle: Not Provided Number Of Devices: 2
Now, searching on the internet it seems that some people are claiming to be using 2×8 GB modules with the same laptop model, BIOS and processor even when the manufacturer still says that this is not supported. If you read through that thread you'll find different users confirming that doing a RAM upgrade worked for them regardless of the manufacturer's official claim.
My question is: is this possible? Which are the implications of the
dmidecode -t 16 output? Is the Maximum Capacity an arbitrary value that can be set/faked by the manufacturer to "force" you to upgrade your whole laptop instead of just upgrading your RAM? Or is it a real physical limitation that would make an upgrade impossible when inserting more than the 8 GB Maximum Capacity?