System Info reporting wrong amount of RAM

[Eph]

Things have become confusing lately with GB representing either 2^30 bytes (the traditional programmer way) or 10^9 bytes (the new IEC way). The old way is being replaced with GiB where a GiB is 2^30 bytes. This leads to a lot of confusion since adoption of GiB is far from universal and GB remains ambiguous until it becomes so.

My Framework laptop has two 16GiB DIMMs installed for a total of 32GiB of RAM. When I run System Info I get this:

System Memory 31.2GiB

Odd...

So, I run dmidecode which reports

Code: Select all

(Handle 0x0015, DMI type 17, 92 bytes
Memory Device
	Array Handle: 0x0014
	Error Information Handle: No Error
	Total Width: 64 bits
	Data Width: 64 bits
	Size: 16384 MB
	Form Factor: SODIMM
	Set: None
	Locator: Controller0-ChannelA-DIMM0
	Bank Locator: BANK 0
	Type: DDR4
	Type Detail: Synchronous
	Speed: 3200 MT/s
	Manufacturer: Crucial Technology
	Serial Number: E55F0A86
	Asset Tag: 9876543210
	Part Number: CT16G4SFRA32A.M16FRS
	Rank: 2
	Configured Memory Speed: 3200 MT/s
	Minimum Voltage: Unknown
	Maximum Voltage: Unknown
	Configured Voltage: 1.2 V
	Memory Technology: DRAM
	Memory Operating Mode Capability: Volatile memory
	Firmware Version: Not Specified
	Module Manufacturer ID: Bank 6, Hex 0x9B
	Module Product ID: Unknown
	Memory Subsystem Controller Manufacturer ID: Unknown
	Memory Subsystem Controller Product ID: Unknown
	Non-Volatile Size: None
	Volatile Size: 16 GB
	Cache Size: None
	Logical Size: None

Handle 0x0016, DMI type 17, 92 bytes
Memory Device
	Array Handle: 0x0014
	Error Information Handle: No Error
	Total Width: 64 bits
	Data Width: 64 bits
	Size: 16384 MB
	Form Factor: SODIMM
	Set: None
	Locator: Controller1-ChannelA-DIMM0
	Bank Locator: BANK 0
	Type: DDR4
	Type Detail: Synchronous
	Speed: 3200 MT/s
	Manufacturer: Crucial Technology
	Serial Number: E55F0B94
	Asset Tag: 9876543210
	Part Number: CT16G4SFRA32A.M16FRS
	Rank: 2
	Configured Memory Speed: 3200 MT/s
	Minimum Voltage: Unknown
	Maximum Voltage: Unknown
	Configured Voltage: 1.2 V
	Memory Technology: DRAM
	Memory Operating Mode Capability: Volatile memory
	Firmware Version: Not Specified
	Module Manufacturer ID: Bank 6, Hex 0x9B
	Module Product ID: Unknown
	Memory Subsystem Controller Manufacturer ID: Unknown
	Memory Subsystem Controller Product ID: Unknown
	Non-Volatile Size: None
	Volatile Size: 16 GB
	Cache Size: None
	Logical Size: None
)

So, the DIMMs do contain 16384MB (or in IEC terms 16384 MiB) as I expected.

My question is why does System Info report 31.2 GiB of RAM instead of 32GiB?

[all41]

all os allocate ram for internal operations
Sys Info is reporting what is currently up for grabs

[Menard]

genenerally it is preallocated by the Graphic card, my APU uses 1 GB of my 8 GB RAM