On Thu, 2010-07-22 at 17:58 +0000, Joseph L. Casale wrote: > >What is a program supposed to do to get at "that extra RAM" then ? > >Just curious ;-) > > AFAIK, it must be specifically compiled for it... --- A PAE enabled Kernel: NO. It is dependent on the mmap() call in the program as in how the memory allocation is done in it. dmesg | grep Memory Memory: 2070724k/2097024k available (2254k kernel code, 25172k reserved, 1149k data, 272k init, 1179520k highmem) cat /proc/mtrr reg00: base=0x00000000 ( 0MB), size=2048MB: write-back, count=1 reg01: base=0xfc000000 (4032MB), size= 64MB: uncachable, count=1 reg02: base=0xfd000000 (4048MB), size= 8MB: write-combining, count=1 Total of Memory Array(s) Attributes : Total Installed Capacity Value : 2048 MB Attributes : Total Installed Capacity Available to the OS Value : 2024 MB For as performance wise some would be amazed at what a 32bit machine on pae can do (prog dependent). Memory allocation is faster than a X86_64. IE locking spin lock... Don't be confused there is a point to stop and go 64Bit only. John