Running Fedora 11 - SMP
ASRock X38TwinTurbo with 4 x 1 Gig memory modules.

In bios PCI Memory Remap is enabled and hardware is reporting proper memory availability.

In order for fedora to boot set kernel parameter mem=4G, otherwise it locks. After start up the OS only reports ~ 3 gigs available.

cat /proc/meminfo
MemTotal: 3062952 kB
MemFree: 1170892 kB
Buffers: 102816 kB
Cached: 1072364 kB
SwapCached: 0 kB
Active: 690656 kB
Inactive: 873820 kB

Here is the mtrr mapping (really think the issue is here in the reg02 mapping) ...

cat /proc/mtrr
reg00: base=0x000000000 ( 0MB), size= 2048MB, count=1: write-back
reg01: base=0x080000000 ( 2048MB), size= 1024MB, count=1: write-back
reg02: base=0x100000000 ( 4096MB), size= 1024MB, count=1: write-back

I wondered if this is an issue with the mtrr cleanup, so I disabled the mtrr cleanup at boot but no dice.

Also, running Fedora 10 x86_64 with enable_mtrr_cleanup the os reported ~ 4 gigs.

Anyone have thoughts on this problem? Do I need to manually script the mtrr layout?