Kernel-PAE not seeing more than 4GB

Linux only sees 4GB.  When I run top this is what it shows;
Mem:   4087288k total,   539200k used,  3548088k free,   124108k buffers
Swap:  2031608k total,        0k used,  2031608k free,   299776k cached
 
Below is the output from dmesg | grep BIOS

BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009f400 (usable)
 BIOS-e820: 000000000009f400 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 00000000dfff3000 (usable)
 BIOS-e820: 00000000dfff3000 - 00000000dfffb000 (ACPI data)
 BIOS-e820: 00000000dfffb000 - 00000000e0000000 (reserved)
 BIOS-e820: 00000000fec00000 - 00000000fed00000 (reserved)
 BIOS-e820: 00000000fee00000 - 00000000fee10000 (reserved)
 BIOS-e820: 00000000ffc00000 - 0000000100000000 (reserved)
 BIOS-e820: 0000000100000000 - 000000011bfff000 (usable)
PCI: BIOS Bug: MCFG area at e0000000 is not E820-reserved
PCI: PCI BIOS revision 2.10 entry at 0xf0096, last bus=12
PCI: Device 0000:00:00.0 not found by BIOS
apm: BIOS not found.
    ide0: BM-DMA at 0x0500-0x0507, BIOS settings: hda:DMA, hdb:pio
    ide1: BM-DMA at 0x0508-0x050f, BIOS settings: hdc:pio, hdd:pio
Contact your BIOS vendor to see if the E752x error registers can be safely un-hidden

Thanks

Upon bootup the BIOS does show 6GB Interesting (I realized that I entered 8GB earlier, that was a mistake, I meant 6GB).   When I run dmidecode it shows the memory;

Handle 0x1000, DMI type 16, 15 bytes.
Physical Memory Array
        Location: System Board Or Motherboard
        Use: System Memory
        Error Correction Type: Single-bit ECC
        Maximum Capacity: 12 GB
        Error Information Handle: Not Provided
        Number Of Devices: 6

Handle 0x1100, DMI type 17, 23 bytes.
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 1024 MB
        Form Factor: DIMM
        Set: 1
        Locator: DIMM 01
        Bank Locator: Not Specified
        Type: DDR
        Type Detail: Synchronous
        Speed: 400 MHz (2.5 ns)

Handle 0x1101, DMI type 17, 23 bytes.
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 1024 MB
        Form Factor: DIMM
        Set: 1
        Locator: DIMM 02
        Bank Locator: Not Specified
        Type: DDR
        Type Detail: Synchronous
        Speed: 400 MHz (2.5 ns)

Handle 0x1102, DMI type 17, 23 bytes.
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 1024 MB
        Form Factor: DIMM
        Set: 2
        Locator: DIMM 03
        Bank Locator: Not Specified
        Type: DDR
        Type Detail: Synchronous
        Speed: 400 MHz (2.5 ns)

Handle 0x1103, DMI type 17, 23 bytes.
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 1024 MB
        Form Factor: DIMM
        Set: 2
        Locator: DIMM 04
        Bank Locator: Not Specified
        Type: DDR
        Type Detail: Synchronous
        Speed: 400 MHz (2.5 ns)

Handle 0x1104, DMI type 17, 23 bytes.
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 1024 MB
        Form Factor: DIMM
        Set: 3
        Locator: DIMM 05
        Bank Locator: Not Specified
        Type: DDR
        Type Detail: Synchronous
        Speed: 400 MHz (2.5 ns)

Handle 0x1105, DMI type 17, 23 bytes.
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 72 bits
        Data Width: 64 bits
        Size: 1024 MB
        Form Factor: DIMM
        Set: 3
        Locator: DIMM 06
        Bank Locator: Not Specified
        Type: DDR
        Type Detail: Synchronous
        Speed: 400 MHz (2.5 ns)

Handle 0x1300, DMI type 19, 15 bytes.
Memory Array Mapped Address
        Starting Address: 0x00000000000
        Ending Address: 0x000FFFFFFFF
        Range Size: 4 GB
        Physical Array Handle: 0x1000
        Partition Width: 0

Handle 0x1400, DMI type 20, 19 bytes.
Memory Device Mapped Address
        Starting Address: 0x00000000000
        Ending Address: 0x0007FFFFFFF
        Range Size: 2 GB
        Physical Device Handle: 0x1100
        Memory Array Mapped Address Handle: 0x1300
        Partition Row Position: 1
        Interleave Position: 1
        Interleaved Data Depth: Unknown

So in part it does see it.  It's strange that it's not showing as available.

Thanks