John R Pierce wrote:
but thats neither here nor there, PAE is a universal issue for any x86 32bit system with 4GB+ ram, with PAE disabled, the BIOS, PCI, AGP or PCI-express, etc IO spaces consume anywheres from .5 to 1GB of the 32bit address space. PAE is a hardware workaround implemented in pretty much all Intel and AMD CPUs made in the last 5+ years, and allows the OS to access more than 4GB of physical address space. PAE introduces some hardware overhead because it involves larger page tables and another level of indirection in the TLB lookups.
CentOS 5 installs defaults to PAE off because there are some systems where PAE is crash-happy. Someone here has already explained how to enable PAE and in fact the original poster tried it and is happy with his full 4GB now.
Well, looks like I'm having quite a bit of a problem then. :-(
I have PAE kernel running, and all I see is 3.2Gb of the 4Gb.
dmidecode gives me this (intel chip):
Handle 0x0000, DMI type 0, 20 bytes. BIOS Information Vendor: Intel Corp. Version: EV91510A.86A.0482.2006.0222.2350
And later this:
Handle 0x0041, DMI type 19, 15 bytes. Memory Array Mapped Address Starting Address: 0x00000000000 Ending Address: 0x000C77FFFFF Range Size: 3192 MB Physical Array Handle: 0x0040 Partition Width: 0
[snip]
Handle 0x0048, DMI type 17, 27 bytes. Memory Device Array Handle: 0x0040 Error Information Handle: 0x003F Total Width: 64 bits Data Width: 64 bits Size: 1024 MB Form Factor: DIMM Set: 2 Locator: J6H2 Bank Locator: CHANNEL B DIMM1 Type: DDR Type Detail: Synchronous Speed: 400 MHz (2.5 ns) Manufacturer: Manufacturer4 Serial Number: SerNum4 Asset Tag: AssetTagNum4 Part Number: PartNum4
Handle 0x0049, DMI type 20, 19 bytes. Memory Device Mapped Address Starting Address: 0x000C0000000 Ending Address: 0x000C6FFFFFF Range Size: 112 MB Physical Device Handle: 0x0048 Memory Array Mapped Address Handle: 0x0041 Partition Row Position: 2 Interleave Position: 2 Interleaved Data Depth: 2
As you can see, the last 1Gb bank is only used at 11%.
Any ideas on why I can't see all 4Gb?