Can not use full capacity of installed ram

I have Aorus Master X570 with Ryzen 9 3950X and separate graphics card (ASROCK Radeon RX 5500 XT Challenger D 8G in PCIe 4 16x slot) I have installed 4x 32GB DDR4 corsair modules (VENGEANCE RGB PRO 64GB (2 x 32GB) DDR4 DRAM 3000MHz C15 Memory Kit) to it which makes 128 GB in total. I have the latest BIOS (F11).

However I'm not able to use all 128 GB. My system only has ~126GB available, more than 2GB are reserved.

Is there some setting in BIOS i need to change to have the full capacity or RAM available? Is this somehow pre-allocated for some internal graphics (some ryzen do have internal GPU).

I'm using Linux (Kubuntu 20.04), here are the outputs from dmesg | grep emory,free and cat /proc/meminfo commands:

root:~# dmesg | grep emory:
[    0.000000] PM: Registered nosave memory: [mem 0x00000000-0x00000fff]
[    0.000000] PM: Registered nosave memory: [mem 0x000a0000-0x000fffff]
[    0.000000] PM: Registered nosave memory: [mem 0x09e02000-0x09ffffff]
[    0.000000] PM: Registered nosave memory: [mem 0x0a200000-0x0a20bfff]
[    0.000000] PM: Registered nosave memory: [mem 0xd733b000-0xd733bfff]
[    0.000000] PM: Registered nosave memory: [mem 0xd7353000-0xd7353fff]
[    0.000000] PM: Registered nosave memory: [mem 0xd7354000-0xd7354fff]
[    0.000000] PM: Registered nosave memory: [mem 0xd7361000-0xd7361fff]
[    0.000000] PM: Registered nosave memory: [mem 0xd73a8000-0xd73a8fff]
[    0.000000] PM: Registered nosave memory: [mem 0xd73b9000-0xd73b9fff]
[    0.000000] PM: Registered nosave memory: [mem 0xd7b73000-0xd7bc9fff]
[    0.000000] PM: Registered nosave memory: [mem 0xda343000-0xda343fff]
[    0.000000] PM: Registered nosave memory: [mem 0xdb75d000-0xdb993fff]
[    0.000000] PM: Registered nosave memory: [mem 0xdbb1c000-0xdbf49fff]
[    0.000000] PM: Registered nosave memory: [mem 0xdbf4a000-0xdcc08fff]
[    0.000000] PM: Registered nosave memory: [mem 0xdf000000-0xdfffffff]
[    0.000000] PM: Registered nosave memory: [mem 0xe0000000-0xf7ffffff]
[    0.000000] PM: Registered nosave memory: [mem 0xf8000000-0xfbffffff]
[    0.000000] PM: Registered nosave memory: [mem 0xfc000000-0xfcffffff]
[    0.000000] PM: Registered nosave memory: [mem 0xfd000000-0xffffffff]
[    0.000000] Memory: 131679596K/134165956K available (14339K kernel code, 2397K rwdata, 4948K rodata, 2712K init, 4992K bss, 2486360K reserved, 0K cma-reserved)
[    0.004807] Freeing SMP alternatives memory: 40K
[    1.915340] Freeing initrd memory: 78264K
[    1.971224] Freeing unused decrypted memory: 2040K
[    1.971517] Freeing unused kernel image memory: 2712K
[    1.996566] Freeing unused kernel image memory: 2008K
[    1.996767] Freeing unused kernel image memory: 1196K
[    2.135665] [TTM] Zone  kernel: Available graphics memory: 65968864 KiB
[    2.135665] [TTM] Zone   dma32: Available graphics memory: 2097152 KiB


root:~# free
              total        used        free      shared  buff/cache   available
Mem:      131937728    18223112    80158388      543632    33556228   111930044
Swap:             0           0           0


root:~# cat /proc/meminfo 
MemTotal:       131937728 kB
MemFree:        80066760 kB
MemAvailable:   111855496 kB
Buffers:          598632 kB
Cached:         32510864 kB
SwapCached:            0 kB
Active:         19166560 kB
Inactive:       30586972 kB
Active(anon):   16643144 kB
Inactive(anon):   547712 kB
Active(file):    2523416 kB
Inactive(file): 30039260 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:               328 kB
Writeback:             0 kB
AnonPages:      16644420 kB
Mapped:           849300 kB
Shmem:            552780 kB
KReclaimable:     472920 kB
Slab:             783896 kB
SReclaimable:     472920 kB
SUnreclaim:       310976 kB
KernelStack:       36304 kB
PageTables:        89220 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:    65968864 kB
Committed_AS:   130765020 kB
VmallocTotal:   34359738367 kB
VmallocUsed:       58688 kB
VmallocChunk:          0 kB
Percpu:            33536 kB
HardwareCorrupted:     0 kB
AnonHugePages:         0 kB
ShmemHugePages:        0 kB
ShmemPmdMapped:        0 kB
FileHugePages:         0 kB
FilePmdMapped:         0 kB
CmaTotal:              0 kB
CmaFree:               0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
Hugetlb:               0 kB
DirectMap4k:     1613640 kB
DirectMap2M:    17209344 kB
DirectMap1G:    116391936 kB

My motherbord: link
My ram: link

I executed memtest couple of times and the modules seems to be working fine. Also lshw shows correct parameters for them.