Comment 1 for bug 287031

I have exactly the same issue on 32 bit Ubuntu Intrepid Ibex 8.10.
My Samsung R60 - XY01 has Intel Core 2 Duo T5250 and BIOS detects full 4Gb.
I tried compiling kernel with PAE support (4GB and 64GB turned on) from 2.6.27 source.

Now i'm running 2.6.27-7-server, was running 2.6.27-7-generic.

free:
                    total used free shared buffers cached
Mem: 2850784 2764372 86412 0 89668 855304

Still 4GB are detected as 2.7Gb.

Here is dmidecode part (don't know if it says something):
..............................
Handle 0x000A, DMI type 16, 15 bytes
Physical Memory Array
 Location: System Board Or Motherboard
 Use: System Memory
 Error Correction Type: None
 Maximum Capacity: 1 GB
 Error Information Handle: Not Provided
 Number Of Devices: 2

Handle 0x000B, DMI type 17, 27 bytes
Memory Device
 Array Handle: 0x000A
 Error Information Handle: No Error
 Total Width: 64 bits
 Data Width: 64 bits
 Size: 2048 MB
 Form Factor: DIMM
 Set: 1
 Locator: J400
 Bank Locator: Channel A0
 Type: DRAM
 Type Detail: Synchronous
 Speed: Unknown
 Manufacturer: Not Specified
 Serial Number: Not Specified
 Asset Tag: Not Specified
 Part Number: Not Specified

Handle 0x000C, DMI type 17, 27 bytes
Memory Device
 Array Handle: 0x000A
 Error Information Handle: No Error
 Total Width: 64 bits
 Data Width: 64 bits
 Size: 2048 MB
 Form Factor: DIMM
 Set: 3
 Locator: J501
 Bank Locator: Channel B0
 Type: DRAM
 Type Detail: Synchronous
 Speed: Unknown
 Manufacturer: Not Specified
 Serial Number: Not Specified
 Asset Tag: Not Specified
 Part Number: Not Specified

Handle 0x000D, DMI type 18, 23 bytes
32-bit Memory Error Information
 Type: OK
 Granularity: Unknown
 Operation: Unknown
 Vendor Syndrome: Unknown
 Memory Array Address: Unknown
 Device Address: Unknown
 Resolution: Unknown

Handle 0x000E, DMI type 19, 15 bytes
Memory Array Mapped Address
 Starting Address: 0x00000000000
 Ending Address: 0x000FFFFFFFF
 Range Size: 4 GB
 Physical Array Handle: 0x000A
 Partition Width: 0

Handle 0x000F, DMI type 20, 19 bytes
Memory Device Mapped Address
 Starting Address: 0x00000000000
 Ending Address: 0x0007FFFFFFF
 Range Size: 2 GB
 Physical Device Handle: 0x000B
 Memory Array Mapped Address Handle: 0x000E
 Partition Row Position: 2
 Interleave Position: 1
 Interleaved Data Depth: 6
.....................................