Is 512MB RAM = 489MB

So, Just sign up new VPS, but the RAM only showing 489MB
Ask support said "The kernel and modules have to go somewhere."
Don't really understand what is the meaning.
Is true?

As my other VPS showing exactly 512MB or 1024MB

This is from new VPS

free -m
total used free shared buffers cached
Mem: 489 98 390 0 30 12
-/+ buffers/cache: 56 433
Swap: 1023 2 1021

cat /proc/meminfo
MemTotal: 501432 kB
MemFree: 400064 kB
Buffers: 30808 kB
Cached: 12608 kB
SwapCached: 1064 kB
Active: 41508 kB
Inactive: 7520 kB
Active(anon): 1348 kB
Inactive(anon): 4348 kB
Active(file): 40160 kB
Inactive(file): 3172 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 1048568 kB
SwapFree: 1046020 kB
Dirty: 4 kB
Writeback: 0 kB
AnonPages: 4740 kB
Mapped: 6220 kB
Shmem: 116 kB
Slab: 40948 kB
SReclaimable: 23440 kB
SUnreclaim: 17508 kB
KernelStack: 584 kB
PageTables: 1396 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 1299284 kB
Committed_AS: 56936 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 2048 kB
VmallocChunk: 34359735356 kB
HardwareCorrupted: 0 kB
AnonHugePages: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 524288 kB
DirectMap2M: 0 kB