Hi everyone!
Intel Manuals Volume 2A 3-207 Instruction Set says following about CPUID:


80000008H EAX Linear/Physical Address size
Bits 07-00: #Physical Address Bits*
Bits 15-8: #Linear Address Bits
Bits 31-16: Reserved = 0
EBX
ECX
EDX
Reserved = 0
Reserved = 0
Reserved = 0
NOTES:
* If CPUID.80000008H:EAX[7:0] is supported, the maximum physical
address number supported should come from this field.

how to get highest memory address using that?

All that will tell you is the maximum physical address lines of the processor's memory controller. If you shift the value 1 left by this number it was give you the size.

There are a number of ways to find the actual physical memory, I would recommend the BIOS int 0x15 ax = 0xE820 function.

THANKS!!!!
I got a perfect memory map with int 15h E820!
Also the main place to load aplications into memory after 100000h