RAM not recognized

[Sean Cavanaugh]

--------------------------------------------------
From: "Paul A. Procacci" <pprocacci at datapipe.com>
Sent: Monday, March 03, 2008 7:45 PM
To: "Cesar Amaya" <csar at 123.com.sv>
Cc: <freebsd-questions at freebsd.org>
Subject: Re: RAM not recognized

> Cesar Amaya wrote:
>> Hello every one, I have installed FreeBSD-7.0_RELEASE on Dell Power Edge 
>> 1950 Quad Core and 4GB of RAM.
>>
>> The problem is that FreeBSD does not recognize all of the RAM.
>> This is part of the dmesg.
>> # dmesg
>> CPU: Intel(R) Xeon(R) CPU           E5420  @ 2.50GHz (2496.28-MHz 
>> 686-class CPU)
>>  Origin = "GenuineIntel"  Id = 0x10676  Stepping = 6
>> 
>> Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
>> 
>> Features2=0xce3bd<SSE3,RSVD2,MON,DS_CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,DCA,<b19>>
>>  AMD Features=0x20100000<NX,LM>
>>  AMD Features2=0x1<LAHF>
>>  Cores per package: 4
>> real memory  = 3484745728 (3323 MB)
>> avail memory = 3405631488 (3247 MB)
>> ACPI APIC Table: <DELL   PE_SC3  >
>> FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs
>> cpu0 (BSP): APIC ID:  0
>> cpu1 (AP): APIC ID:  1
>> cpu2 (AP): APIC ID:  2
>> cpu3 (AP): APIC ID:  3
>> ioapic0: Changing APIC ID to 4
>> ioapic0 <Version 2.0> irqs 0-23 on motherboard
>>
>> Can anyone give me some light in this issue?
>> Thank you very much!!!
>>
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> Forgot to CC list............
>
> This is not a problem of FreeBSD but of i386/x86 architecture which max 
> memory limit is 4GB i theory and 3-3.5GB in practice, you can use PAE to 
> use 36bit addressing (instead of default 32bit) for memory to get full 4GB 
> on i386 but you will not be able to have loadable kernel modules for 
> example, other sollution for this is using amd64/64bit FreeBSD, where you 
> will have full 4GB and even more without any problems.
>

for the 4 gig limit, you have to take in account that the limit is for ALL 
addressable memory space in the computer, this includes video card memory as 
well as resources necessary to run system level stuff like your IDE or SCSI 
controller and any extra firmware may be present on your system. if you want 
to use more than 3 gigs of ram, you HAVE to run AMD64/x64 version of your 
operating system (even windows would have same exact issue).

-Sean