memory

x86_64 Memory Map When Boot

x86_64 Memory Map When Boot

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Linux version 3.6.0-rc1+ (martin@fc17) (gcc version 4.7.0 20120507 (Red Hat 4.7.0-5) (GCC) ) #9 SMP Sun Aug 12 09:42:26 CST 2012
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[martin@fc17 Documents]$ cat bios.e820.diff 
boot.1G.log:BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
boot.1G.log:BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
boot.1G.log:BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
boot.1G.log:BIOS-e820: [mem 0x0000000000100000-0x000000003ffeffff] usable
boot.1G.log:BIOS-e820: [mem 0x000000003fff0000-0x000000003fffffff] ACPI data
boot.1G.log:BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
boot.2G.log:BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
boot.2G.log:BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
boot.2G.log:BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
boot.2G.log:BIOS-e820: [mem 0x0000000000100000-0x000000007ffeffff] usable
boot.2G.log:BIOS-e820: [mem 0x000000007fff0000-0x000000007fffffff] ACPI data
boot.2G.log:BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
boot.4G.log:BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
boot.4G.log:BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
boot.4G.log:BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
boot.4G.log:BIOS-e820: [mem 0x0000000000100000-0x00000000dffeffff] usable
boot.4G.log:BIOS-e820: [mem 0x00000000dfff0000-0x00000000dfffffff] ACPI data
boot.4G.log:BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
boot.4G.log:BIOS-e820: [mem 0x0000000100000000-0x000000011fffffff] usable
boot.6G.log:BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
boot.6G.log:BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
boot.6G.log:BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
boot.6G.log:BIOS-e820: [mem 0x0000000000100000-0x00000000dffeffff] usable
boot.6G.log:BIOS-e820: [mem 0x00000000dfff0000-0x00000000dfffffff] ACPI data
boot.6G.log:BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
boot.6G.log:BIOS-e820: [mem 0x0000000100000000-0x000000019fffffff] usable

##1G / 2G / 4G / 6G compare:

###Same

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1 boot.1G.log:BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
2 boot.2G.log:BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
3 boot.4G.log:BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
4 boot.6G.log:BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
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6 boot.1G.log:BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
7 boot.2G.log:BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
8 boot.4G.log:BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
9 boot.6G.log:BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
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11 boot.1G.log:BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
12 boot.2G.log:BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
13 boot.4G.log:BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
14 boot.6G.log:BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
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26 boot.1G.log:BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
27 boot.2G.log:BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
28 boot.4G.log:BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
29 boot.6G.log:BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved

###Diff

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16 boot.1G.log:BIOS-e820: [mem 0x0000000000100000-0x000000003ffeffff] usable
17 boot.2G.log:BIOS-e820: [mem 0x0000000000100000-0x000000007ffeffff] usable
18 boot.4G.log:BIOS-e820: [mem 0x0000000000100000-0x00000000dffeffff] usable
19 boot.6G.log:BIOS-e820: [mem 0x0000000000100000-0x00000000dffeffff] usable
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21 boot.1G.log:BIOS-e820: [mem 0x000000003fff0000-0x000000003fffffff] ACPI data
22 boot.2G.log:BIOS-e820: [mem 0x000000007fff0000-0x000000007fffffff] ACPI data
23 boot.4G.log:BIOS-e820: [mem 0x00000000dfff0000-0x00000000dfffffff] ACPI data
24 boot.6G.log:BIOS-e820: [mem 0x00000000dfff0000-0x00000000dfffffff] ACPI data

Diff(only 4G, 6G need this range). 

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31 boot.4G.log:BIOS-e820: [mem 0x0000000100000000-0x000000011fffffff] usable
32 boot.6G.log:BIOS-e820: [mem 0x0000000100000000-0x000000019fffffff] usable